sci.electronics.repair - 25 new messages in 9 topics - digest

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sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

==============================================================================
TOPIC: Fuse: fast blown vs slow blown
http://groups.google.com/group/sci.electronics.repair/t/075c97d6b6b6e1f0?hl=en
==============================================================================

== 1 of 5 ==
Date: Tues, May 31 2011 11:47 am
From: Jamie

Jeff Liebermann wrote:

> On Tue, 31 May 2011 09:02:08 -0700, Tim Wescott <tim@seemywebsite.com>
> wrote:
>
>
>>On 05/31/2011 08:57 AM, Man-wai Chang wrote:
>>
>>>>Your best bet is to get the right fuse, and at least try to fix the
>>>>fault before you turn the equipment on with your shiny new fuse.
>>>
>>>For a multimeter, is it always better to use a fast blow fuse?
>
>
>>Check to make sure that the fuse isn't being used as the current shunt
>>-- if it is, then you don't just need the right current rating, you need
>>a matched fuse.
>
>
> Chuckle. If a fuse were used as a current shunt, then when the fuse
> blows, instead of a few millivolts across the fuse, the meter now gets
> the full voltage of whatever is being measured. The fuse holder
> contact resistance will probably be larger than the wire resistance in
> the fuse (fast blow). I don't think anyone uses a fuse as a current
> shunt.
>
Hush, you wasn't suppose to notice that! Built in obsolescence.

Jamie

== 2 of 5 ==
Date: Tues, May 31 2011 12:18 pm
From: "Michael A. Terrell"

Jeff Liebermann wrote:
>
> On Tue, 31 May 2011 09:02:08 -0700, Tim Wescott <tim@seemywebsite.com>
> wrote:
>
> >On 05/31/2011 08:57 AM, Man-wai Chang wrote:
> >>> Your best bet is to get the right fuse, and at least try to fix the
> >>> fault before you turn the equipment on with your shiny new fuse.
> >>
> >> For a multimeter, is it always better to use a fast blow fuse?
>
> >Check to make sure that the fuse isn't being used as the current shunt
> >-- if it is, then you don't just need the right current rating, you need
> >a matched fuse.
>
> Chuckle. If a fuse were used as a current shunt, then when the fuse
> blows, instead of a few millivolts across the fuse, the meter now gets
> the full voltage of whatever is being measured. The fuse holder
> contact resistance will probably be larger than the wire resistance in
> the fuse (fast blow). I don't think anyone uses a fuse as a current
> shunt.

Too hard to calibrate. :)

I used some test fixtures on the PRC-77 QA line for module
interchangability that had to be returned to the cal lab if a module
blew a fuse. !@#$%^&*( RCA/NATO design. @#$%^&*

--
It's easy to think outside the box, when you have a cutting torch.

== 3 of 5 ==
Date: Tues, May 31 2011 12:38 pm
From: John Robertson

Man-wai Chang wrote:
>
> How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
> slow-brown one?
>

Hope this helps answer your question!

http://flippers.com/fuses.html

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

== 4 of 5 ==
Date: Tues, May 31 2011 2:41 pm
From: Baron

Man-wai Chang Inscribed thus:

>> It has 18 volts instead of 12 volts, but it uses the same diameter
>> coaxial connector. A fast fuse protects in 400 microseconds, but the
>> slow blow does not blow that fast so the 45 nanometer digital device
>> gets melted in 1000 microseconds.
>
> Is the 13A BS1362 fuse a fast blow one?

No !

--
Best Regards:
Baron.

== 5 of 5 ==
Date: Tues, May 31 2011 6:26 pm
From: "Phil Allison"

"Jeff Liebermann"

>>
>>Is the 13A BS1362 fuse a fast blow one?
>
> That's the number of the plug, not the fuse:

** Funny, I have any number of fuses in my bins with "BS 1362" printed on
them.

> <http://en.wikipedia.org/wiki/BS_1363>
>
> It does have a fuse inside, but I don't know the value or type.

**From the very same Wiki:

http://en.wikipedia.org/wiki/BS_1363#Fuses

A 13A, BS 1362 fuse is very much a Slow Blow !

.... Phil

==============================================================================
TOPIC: NiMH new battery conditioning
http://groups.google.com/group/sci.electronics.repair/t/642feb09361f607e?hl=en
==============================================================================

== 1 of 7 ==
Date: Tues, May 31 2011 11:27 am
From: dplatt@radagast.org (Dave Platt)

In article <3kt8u69j7d6i3cetop4hgcjfsv92ek2s8r@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

>True for the Duracell, which recommends 205ma for 15 hrs to recharge
>printed on the cell. The Energizer Recharge battery doesn't specify a
>charge current:
><http://data.energizer.com/PDFs/nh15-2000.pdf>
>However, the recommended battery charger is a quick charger:
><http://data.energizer.com/PDFs/ch15mn2.pdf>
>with a 15 minute charge time.
>
>I've been testing batteries since about 2005 while working on a
>product that I won't discuss. However, I will point out that many
>NiCd batteries can be quick charged at ridiculously high rates, as
>long as certain (unspecified) conditions are met. If you don't mind,
>I'll leave this unsubstantiated.
>
>Incidentally, the Sanyo ENELOOP battery data sheet recommends fast
>charging at 2A for 1.1 hrs:
><http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>

Interesting. Another page in the Sanyo FAQ section (at
http://us.sanyo.com/eneloop/FAQs) says:

Though it is possible to charge an eneloop battery in a "Quick
Charger", it is not recommended. We recommend charging eneloop
batteries in a NiMh charger that is 2 hours or more. Charging eneloop
batteries in a "Quick Charger" can reduce the overall life of the
battery.

I've read statements to the effect that one reason you would want to
use moderately-fast charging rates (e.g. 1C) rather than the low rates
traditional for most NiCd cells (e.g. 0.1C), is that the NiMH cells
will heat up more abruptly when they reach full charge, and the
charging power starts turning into heat rather than electrochemical
potential. The abrupt rise in cell temperature is easier to detect
reliably (via a temperature sensor and/or due to the zero-delta-V
effect) than if you were charging more slowly... and thus a more
reliable "full charge, stop now!" shutoff circuit can be designed, and
avoid overcharging (which I understand NiMH cells don't tolerate at
all well).

>Incidentally, all of the marine radios I helped design were required
>to function down to 10.0VDC applied power. They couldn't reach rated
>TX power at 70% of rated voltage, but still had to belch at least a
>few watts of RF and remain functional.

A good decision! It bothers me that a lot of HF and VHF radios "poop
out" at much below 12 volts.

>I'm rather mystified by the results. Although the improvement in
>capacity after 3 charge-discharge cycles is minor (10-15%), it still
>seems for real. My previous tests didn't show such an increase in
>capacity. Instead, it showed a deterioration in capacity. However, I
>was testing for something quite different, and was working with a mix
>of old and new cells.

For what it's worth, the Sanyo FAQ page cited above does make
reference to the break-in effect:

Should I store my batteries charged or uncharged?

If stored with charge, it is possible that when you return to use
the battery there may still be some charge left in the battery,
therefore it will enable you to use it right then and there. Also,
by keeping some charge in the battery, it will require you to
"cycle" the battery fewer times until it reaches its peak charge.
If you store them with no charge, you will have to "cycle" the
battery multiple times until it reaches its peak charge.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

== 2 of 7 ==
Date: Tues, May 31 2011 12:54 pm
From: "William Sommerwerck"

> Though it is possible to charge an eneloop battery in a
> "Quick Charger", it is not recommended. We recommend
> charging eneloop batteries in a NiMh charger that is [sic]
> 2 hours or more. Charging eneloop batteries in a "Quick
> Charger" can reduce the overall life of the battery.

A two-hour charge is, by any reasonable standard, a "quick charge". It would
be at least 0.5C -- hardly a slow charge.

== 3 of 7 ==
Date: Tues, May 31 2011 6:46 pm
From: "Phil Allison"

"William Sommerwanker"
>>
>> Though it is possible to charge an eneloop battery in a
>> "Quick Charger", it is not recommended. We recommend
>> charging eneloop batteries in a NiMh charger that is [sic]
>> 2 hours or more. Charging eneloop batteries in a "Quick
>> Charger" can reduce the overall life of the battery.
>
> A two-hour charge is, by any reasonable standard, a "quick charge". It
> would
> be at least 0.5C -- hardly a slow charge.
>

** Standard charge for a NiMH is 16 hours at 0.1C.

Quick chargers deliver about 0.2C to 0.5 C

Fast chargers deliver 1C to 4C ( ouch ! )

Because NiMH ( AA, A or 9V ) cells vary widely in rated capacity - the same
charger has multiple rates.

So called " simple " chargers have a timer as the only cut out.

A 4C fast charger that only has a timer is a lethal weapon.

IME - the worst offenders in supplying chargers that are practically
guaranteed to ruin the cells are the battery makers - ie Energiser, Varta
and Sanyo.

Funny about that.

.... Phil

== 4 of 7 ==
Date: Tues, May 31 2011 7:11 pm
From: "William Sommerwerck"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:94ljveFq68U1@mid.individual.net...

> "William Sommerwanker"

I thought you'd reformed. But you haven't. Why don't you just go back to
being a foul-mouthed jerk? That's what you want, isn't it? You want people
to hate you, because it makes you feel superior.

The worst part is that when you aren't making nasty remarks, you almost
always have somthing worth hearing.

Our own little Eric Cartman. How charming.

>>> Though it is possible to charge an eneloop battery in a
>>> "Quick Charger", it is not recommended. We recommend
>>> charging eneloop batteries in a NiMh charger that is [sic]
>>> 2 hours or more. Charging eneloop batteries in a "Quick
>>> Charger" can reduce the overall life of the battery.

>> A two-hour charge is, by any reasonable standard, a "quick charge".
>> It would be at least 0.5C -- hardly a slow charge.

> ** Standard charge for a NiMH is 16 hours at 0.1C.
> Quick chargers deliver about 0.2C to 0.5 C
> Fast chargers deliver 1C to 4C (ouch!)
> Because NiMH ( AA, A or 9V ) cells vary widely in rated capacity --
> the same charger has multiple rates.

> So-called "simple" chargers have a timer as the only cutout.
> A 4C fast charger that only has a timer is a lethal weapon.

> IME -- the worst offenders in supplying chargers that are practically
> guaranteed to ruin the cells are the battery makers -- ie Energizer,
> Varta, and Sanyo.
> Funny about that.

As they sell batteries, why should it be funny?

Based on my experience at Microsoft Hardware, and MAHA's documentation, 0.1C
is not considered an appropriate charge rate for NiMH cells. Higher rates
are recommended, supposedly because they pump more charge into the cell
before the cutoff voltage or temperature is reached.

I rarely charge faster than 0.3C. That's just basic cowardice on my part.

== 5 of 7 ==
Date: Tues, May 31 2011 7:35 pm
From: "Phil Allison"

"William Sommerwanker = Colossal FUCKWIT "
>
>>> A two-hour charge is, by any reasonable standard, a "quick charge".
>>> It would be at least 0.5C -- hardly a slow charge.
>
>> ** Standard charge for a NiMH is 16 hours at 0.1C.
>> Quick chargers deliver about 0.2C to 0.5 C
>> Fast chargers deliver 1C to 4C (ouch!)
>> Because NiMH ( AA, A or 9V ) cells vary widely in rated capacity --
>> the same charger has multiple rates.
>
>> So-called "simple" chargers have a timer as the only cutout.
>> A 4C fast charger that only has a timer is a lethal weapon.
>
>> IME -- the worst offenders in supplying chargers that are practically
>> guaranteed to ruin the cells are the battery makers -- ie Energizer,
>> Varta, and Sanyo.
>> Funny about that.
>
> As they sell batteries, why should it be funny?

** FFS - the irony is pretty damn strong.

Not to mention being contrary to consumer law.

> Based on my experience at Microsoft Hardware, and MAHA's documentation,
> 0.1C
> is not considered an appropriate charge rate for NiMH cells.

** Totally IRRELEVANT.

For * loose cells * sold to the public and in the absence of " smart "
chargers that treat each cell as in individual - it is the only reliably
safe method.

> Higher rates
> are recommended, supposedly because they pump more charge into the cell
> before the cutoff voltage or temperature is reached.

** Requires a smart charger, matched packs of cells et alia ad nauseam.

A whole different ball game.

> I rarely charge faster than 0.3C.

** Still well capable of ruining NiMH cells left on charge for too long.

BTW:

Ruining refers to a simultaneous loss of capacity and LARGE increases in
self discharge rate and internal resistance.

.... Phil

== 6 of 7 ==
Date: Tues, May 31 2011 8:21 pm
From: "William Sommerwerck"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:94lmqvFcfeU1@mid.individual.net...

>> Higher rates
>> are recommended, supposedly because they pump more charge
>> into the cell before the cutoff voltage or temperature is reached.

> ** Requires a smart charger, matched packs of cells et alia ad nauseam.
> A whole different ball game.

Not for me. I own two smart chargers.

>> I rarely charge faster than 0.3C.

> ** Still well capable of ruining NiMH cells left on charge for too long.

See preceding.

== 7 of 7 ==
Date: Tues, May 31 2011 8:24 pm
From: "Phil Allison"

"William Sommerwanker = Context Shifter and LIAR "

** DROP FUCKING DEAD

==============================================================================
TOPIC: Is there a fuse on a Samsung SV4000?
http://groups.google.com/group/sci.electronics.repair/t/d375f8c622c671d0?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, May 31 2011 12:19 pm
From: PlainBill@yawhoo.com

On Tue, 31 May 2011 10:16:29 -0700 (PDT), myfathersson
<licensedtoquill@gmail.com> wrote:

>Sorry, let me re-phrase that: DOWNLOADING NOW means you have to click
>on some virtually hidden link two thirds down on the page to download
>
>Doing that downloads something called a .djvu file. which requires
>installing Nuance Software .pdf reader.
>
>When you do that, it just tells you that it cant open the mysterious
>286kb sv4000w.djvu file you have just downloaded!
That's why intelligent people avoid places like eserviceinfo and the
dozens of sites that give bogus hits on Google.

Instead, go to Elektrotanya. The site is in Poland, the menus are in
both Polish and English. The site sometimes is flaky; as a registered
user (registration is free) I have not had problems downloading when
using a decent browser (FoxFire). For those who are offended by
Polish menues, registration, or Foxfire, I can only say C'est la vie!

http://elektrotanya.com/?q=showresult&megnev=samsung&megnev2=sv-4000&kategoria=&kat2=all

PlainBill

== 2 of 2 ==
Date: Tues, May 31 2011 12:45 pm
From: "Michael A. Terrell"

myfathersson wrote:
>
> Sorry, let me re-phrase that: DOWNLOADING NOW means you have to click
> on some virtually hidden link two thirds down on the page to download
>
> Doing that downloads something called a .djvu file. which requires
> installing Nuance Software .pdf reader.
>
> When you do that, it just tells you that it cant open the mysterious
> 286kb sv4000w.djvu file you have just downloaded!

That's because it's not a .PDF file. You need a DJVU viewer:

http://windjview.sourceforge.net/

--
It's easy to think outside the box, when you have a cutting torch.

==============================================================================
TOPIC: microwave oven stopping prematurely, repairable?
http://groups.google.com/group/sci.electronics.repair/t/a4366967d76451a5?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, May 31 2011 1:21 pm
From: Cydrome Leader

whit3rd <whit3rd@gmail.com> wrote:
> If you're OK with tools, and can discharge the capacitor
> safely, consider disassembling the oven and cleaning it.
>
> An insect getting carbonized in the HV section could be
> the only problem here, and you gotta scrub the carbon track
> away to fix that.

==============================================================================
TOPIC: Introduction of PIC in my School
http://groups.google.com/group/sci.electronics.repair/t/fecb73ca77e41f85?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, May 31 2011 2:56 pm
From: "fynnashba@yahoo.com"

Hi friends and good pals out there,
I want to introduce Micro-controllers in my schools electronics
curriculum as it is fast replacing traditional electronics. I need
very good books, Lab equipment and may be a course outline on PICs for
my students. Where do I get all these?
THANKS.

== 2 of 2 ==
Date: Tues, May 31 2011 4:19 pm
From: Jamie

fynnashba@yahoo.com wrote:

> Hi friends and good pals out there,
> I want to introduce Micro-controllers in my schools electronics
> curriculum as it is fast replacing traditional electronics. I need
> very good books, Lab equipment and may be a course outline on PICs for
> my students. Where do I get all these?
> THANKS.
http://www.microchip.com/

==============================================================================
TOPIC: Power transistor question...
http://groups.google.com/group/sci.electronics.repair/t/48e3a91c572ef00c?hl=en
==============================================================================

== 1 of 4 ==
Date: Tues, May 31 2011 3:34 pm
From: Jamie

Dave wrote:

> "Phil Allison" <phil_a@tpg.com.au> wrote in message
> news:94j1ebFms1U1@mid.individual.net...
>
>>"Meat Plow"
>>
>>
>>>>http://www.youtube.com/watch?v=zEA5MfllPdg
>>>
>>>Not a bad little meter for the $$$$. Anyone who does work on consumer
>>>electronics ought to have one or something similar. Removes a lot of
>>>guess work.
>>
>>
>>** I disagree.
>>
>>An LCR meter is more useful for design and production than in servicing.
>>
>>Many low cost DMMs include capacitance ranges that can measure from a few
>>pF up to 200 or 2000uF.
>>
>>A dedicated ESR meter handles electros just fine while in circuit - and
>>lets you test all kinds of cells too, which an LCR meter often cannot.
>>
>>Any DMM can read the resistance of an inductor or transformer winding.
>>
>>The only function left is to measure inductors for value.
>>
>>
>>.... Phil
>>
>
>
> Wanted to thank *everyone* for the info and encouragement I have received in
> this discussion. Bottom line for me, at least for now, is simply don't test
> in-circuit (pop one lead and then test after discharging). Have also found
> a ton of material on youtube and the net that convinces me to get a
> dedicated ESR meter (or possibly build one.) Anyway, thanks all for a very
> enlightening discussion.
>
> Take it easy...
>
> Dave
>
>
I use a cheap B&K LCR, it does in circuit beautifully.

Jamie

== 2 of 4 ==
Date: Tues, May 31 2011 3:51 pm
From: Meat Plow

On Tue, 31 May 2011 12:17:38 +1000, Phil Allison wrote:

> "Meat Plow"
>
>>> http://www.youtube.com/watch?v=zEA5MfllPdg
>>
>> Not a bad little meter for the $$$$. Anyone who does work on consumer
>> electronics ought to have one or something similar. Removes a lot of
>> guess work.
>
>
> ** I disagree.
>
> An LCR meter is more useful for design and production than in servicing.
>
> Many low cost DMMs include capacitance ranges that can measure from a
> few pF up to 200 or 2000uF.
>
> A dedicated ESR meter handles electros just fine while in circuit - and
> lets you test all kinds of cells too, which an LCR meter often cannot.
>
> Any DMM can read the resistance of an inductor or transformer winding.
>
> The only function left is to measure inductors for value.
>
>
> .... Phil

I'd like to see the meter described test at a higher frequency but other
than that I can't find much else wrong. I've been relying on an old Tenma
cap meter for years. It's gets you in the ball park. And there were
reliable repairs before LCR and ESR meters. I know, been at it from high
school back in 1970. These days I tend to shy away from anything I need
an ESR meter for. Plenty of vintage stuff out there that people like to
keep going.

--
Live Fast Die Young, Leave A Pretty Corpse

== 3 of 4 ==
Date: Tues, May 31 2011 6:34 pm
From: "Phil Allison"

"Meat Plow"
>
> I'd like to see the meter described test at a higher frequency but other
> than that I can't find much else wrong. I've been relying on an old Tenma
> cap meter for years. It's gets you in the ball park. And there were
> reliable repairs before LCR and ESR meters. I know, been at it from high
> school back in 1970. These days I tend to shy away from anything I need
> an ESR meter for. Plenty of vintage stuff out there that people like to
> keep going.

** ESR meters are MOST useful with older equipment, particularly valve
amplifiers.

All those electros are old and have been running in a hot environment.

..... Phil

== 4 of 4 ==
Date: Tues, May 31 2011 8:32 pm
From: "Dave"

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:QVdFp.9148$rq2.7889@newsfe12.iad...
> Dave wrote:
>
>> "Phil Allison" <phil_a@tpg.com.au> wrote in message
>> news:94j1ebFms1U1@mid.individual.net...
>>
>>>"Meat Plow"
>>>
>>>
>>>>>http://www.youtube.com/watch?v=zEA5MfllPdg
>>>>
>>>>Not a bad little meter for the $$$$. Anyone who does work on consumer
>>>>electronics ought to have one or something similar. Removes a lot of
>>>>guess work.
>>>
>>>
>>>** I disagree.
>>>
>>>An LCR meter is more useful for design and production than in servicing.
>>>
>>>Many low cost DMMs include capacitance ranges that can measure from a few
>>>pF up to 200 or 2000uF.
>>>
>>>A dedicated ESR meter handles electros just fine while in circuit - and
>>>lets you test all kinds of cells too, which an LCR meter often cannot.
>>>
>>>Any DMM can read the resistance of an inductor or transformer winding.
>>>
>>>The only function left is to measure inductors for value.
>>>
>>>
>>>.... Phil
>>>
>>
>>
>> Wanted to thank *everyone* for the info and encouragement I have received
>> in this discussion. Bottom line for me, at least for now, is simply
>> don't test in-circuit (pop one lead and then test after discharging).
>> Have also found a ton of material on youtube and the net that convinces
>> me to get a dedicated ESR meter (or possibly build one.) Anyway, thanks
>> all for a very enlightening discussion.
>>
>> Take it easy...
>>
>> Dave
>>
>>
> I use a cheap B&K LCR, it does in circuit beautifully.
>
> Jamie
>
>

Hey Jamie, thanks for the note. So, how do you perform an in-circuit ESR
test on a suspect cap? Do you bother to discharge it, or do you just let
the circuitry around the cap do that? And how reliable are the numbers you
come up with? I tried to do an in-circuit test today on a cap and thought I
had gotten lucky with my first shot. A 10uF @ 100V cap gave me an ESR
reading of 42.15 in-circuit, but when I popped it out and tested it again it
dropped to 0.12. big difference! Still trying to figure out what I might
have been doing wrong...

Have since discovered a different cap that may actually be the problem. A
.22uF @ 50V cap with an ESR reading of 25+ ohms. Am thinking this component
may be where the vertical hold sync pulse gets lost, as it feeds an
oscillator/mixer transistor which feeds the output transistor of the
vertical hold circuitry. All of this two days after I discovered I had an
ESR meter and didn't know it. <shaking head>

Dave

==============================================================================
TOPIC: Request transistor cross reference
http://groups.google.com/group/sci.electronics.repair/t/6d311b79499b89d6?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, May 31 2011 3:32 pm
From: jjb_at_northstate_dot_net@foo.com (kaplanB)

kaplanB had written this in response to
http://www.electrondepot.com/repair/Re-Request-transistor-cross-reference-126006-.htm
:
I reenter the discussion with a bit of trepidation as I'm am just a pastor
trying to fix his cooktop, not an
electrical engineer.

I have learned a LOT from your posts and this adventure. I think I have
learned enough to say that what
I'm trying to find a substitute for (Shindengen T30G40) is not an IGBT or
a NPN. It is a PNP! My thinking
is based on three main factors.

I've drawn my own schematic and the cooktop (Kenmore 564.4498512) seems to
look like a "quasi-
resonant" circuit I found when researching induction cooktop designs.
These designs use PNP
transistor.

Second, the voltage at the base, measured on a working element, is -56 Vdc
when idle and -60 Vdc
when energized. Doesn't' that "turn on" a PNP transistor?

Third, pulled the transistors off the board and one of the three power
transistors tests OK as a PNP.

When we all thought this was an NPN I had agreed with Dr. Ornitz's
assessment that an On Sem
MJW18020 would perhaps work as a substitute. Now, I'm looking for a PNP
version but having no luck
so far.

I'm thankful for all the "wise guys" who weigh in on this issue.

Kap B

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== 2 of 2 ==
Date: Tues, May 31 2011 4:14 pm
From: "Dave M"

kaplanB wrote:
> kaplanB had written this in response to
> http://www.electrondepot.com/repair/Re-Request-transistor-cross-reference-126006-.htm
>>
> I reenter the discussion with a bit of trepidation as I'm am just a
> pastor trying to fix his cooktop, not an
> electrical engineer.
>
> I have learned a LOT from your posts and this adventure. I think I
> have learned enough to say that what
> I'm trying to find a substitute for (Shindengen T30G40) is not an
> IGBT or a NPN. It is a PNP! My thinking
> is based on three main factors.
>
> I've drawn my own schematic and the cooktop (Kenmore 564.4498512)
> seems to look like a "quasi-
> resonant" circuit I found when researching induction cooktop designs.
> These designs use PNP transistor.
>
> Second, the voltage at the base, measured on a working element, is
> -56 Vdc when idle and -60 Vdc
> when energized. Doesn't' that "turn on" a PNP transistor?

Not necessarily... You have to measure the base voltage in respect to the
emitter. Assuming that it's a silicon device, you should see -0.65V
to -0.8V at the base with respect to the emitter. That will turn a PNP
transistor on. If the difference in voltage between base and emitter less
than 0.65V, then the transistor isn't on.

> Third, pulled the transistors off the board and one of the three power
> transistors tests OK as a PNP.

Questionable assumption... How do you know the others are PNP units? Do
they have the same part numbers?

>
> Kap B
>

Here's a quick spec on the T30G40 transistor:

Si NPN Power BJT
Shindengen Electric Mfg. Co., Ltd.
V(BR)CEO (V)=400
V(BR)CBO (V)=800
I(C) Abs.(A) Collector Current=30
Absolute Max. Power Diss. (W)=200
h(FE) Min. Static Current Gain=80
f(T) Min. (Hz) Transition Freq=7.0M
t(d) Max. (s) Delay time.=3.0u
t(s) Max. (s) Storage time.=3.0u
t(f) Max. (s) Fall time.=1.0u
Package=SIP
Military=N

That indicates that it's an NPN unit; not PNP. Are you sure that you're
testing the transistors correctly? Maybe you should post a quick narrative
on how you're trying to troubleshoot. And be careful that you know the
polarity of the test leads of the ohms function of your multimeter... A few
will fool you.

--
David
dgminala at mediacombb dot net

==============================================================================
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SHIRT,SHIRTS,HOODY,EYEGLASS,CAP,SHAWL,WALLT) and so on.
http://groups.google.com/group/sci.electronics.repair/t/1ee83c788187e854?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, May 31 2011 5:50 pm
From: jialiu

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on) free shipping http://www.24hours-online.com/

==============================================================================
TOPIC: zebra connector
http://groups.google.com/group/sci.electronics.repair/t/22ac512ae9f1d16c?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, May 31 2011 6:00 pm
From: "Shaun"

"Vale" wrote in message news:jK8Fp.29619$GZ3.6759@tornado.fastwebnet.it...

"Jeff Liebermann" <jeffl@cruzio.com> ha scritto nel messaggio
news:ev1au6l4fk6hevq9fvne7qhm8q5cp0qqrg@4ax.com...
> On Mon, 30 May 2011 17:43:17 +0200, "Vale" <vale@fastwebnet.it> wrote:
>
>>My expensive multimeter has got broken plastic pins that hold the lcd
>>disply
>>on the pcb.
>

Thanks all.I solved, hope for long time.
I've been luky, the dirt that was on the meter case display window was
perfectly corresponding to the dirt line on the display.
So I found the right position.
It has been not so easy to align the display on pcb, I supplied the meter
with a voltage, tried hundreds of positions until it displaied the rights
measurement.
I got help from a pair of chinese spring loaded clamps to firmly block the
display and put some drops of cyanoacrylate on corners.
Than used plenty of epoxy glue to make it stable.
The meter now works quite perfectly, only the last digit is incomplete, but
I'm happy anyway.
At least that experience has provided more knowledge to zebra gadgets.
Thanks everybody and....don't keep your meters too clean!

What brand is your meter? You can probably order parts for it if it is not
too old. When you do order parts, order new zebra strips aswell.

Shaun

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sci.electronics.repair - 25 new messages in 6 topics - digest

11:42 AM Penedão 0 comments

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

* NiMH new battery conditioning - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/642feb09361f607e?hl=en
* zebra connector - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/22ac512ae9f1d16c?hl=en
* Valves badged Orange , rebadged what make? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/b405f7894dddeac4?hl=en
* WHAT IS ISLAM? ???????? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/71561ac87a746849?hl=en
* Fuse: fast blown vs slow blown - 16 messages, 7 authors
http://groups.google.com/group/sci.electronics.repair/t/075c97d6b6b6e1f0?hl=en
* Is there a fuse on a Samsung SV4000? - 3 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/d375f8c622c671d0?hl=en

== 1 of 1 ==
Date: Mon, May 30 2011 10:57 pm
From: "Phil Allison"

"Jeff Liebermann"
>
>>** You got something against NiMh cells ?
>
> Yep. I don't like them.

** Wanker.

>>I would never mistreat NiMH AA cells the way you just have.
>
> I didn't have time to do it the right way (20 hr discharge).

** The 15 min charging was the abuse - fool.

> I can do
> it again with a longer discharge time and lower current.

** The 15 min charging was the abuse - fool.

>>15 minute charging is absurd for any cell NOT designed for such abuse - it
>>causes overheating with new cells and destruction of older ones.
>
> True for the Duracell,

** True for all of them - fool.

> However, the recommended battery charger is a quick charger:
> <http://data.energizer.com/PDFs/ch15mn2.pdf>
> with a 15 minute charge time.

** They would - since they sell the fucking things.

Energiser sell a whole range of chargers designed to destroy NiMh cells.

Means they sell more cells.

> I've been testing batteries since about 2005

** I've been doing it since 1979.

> However, I will point out that many
> NiCd batteries can be quick charged at ridiculously high rates,

** Only a rare few, specially designed NiCds were designed for it -
Sanyo's red " F " cells being one.

The issue is the HIGH probability of OVERCHARGING and hence over heating
with consequent internal damage.

> Incidentally, the Sanyo ENELOOP battery data sheet recommends fast
> charging at 2A for 1.1 hrs:
> <http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>

** Got nothing to do with a 15 minute charge in a cheap POS charger like you
did.

>>A 1C discharge test will never give the rated capacity figure with NiCd or
>>NiMH.
>
> I indicated that in my posting as:
>
>> I didn't want to wait 20 hrs per test to get the official rated
>> capacity, so I elected to run the tests at 1C which resulted in about
>> a 45 minute test, but also resulted in a much lower capacity result.

** Will you admit to being a raving lunatic ???

And save me the trouble of demonstrating it to the world over and over.

>>IME - the idea that new cells have a "running in "period is a MYTH
>>invented by retailers back in the 1970s when consumers were first sold AA
>>and C size NiCds and found their performance disappointing when compared
>>to
>>alkalines.
>
> Maybe.

** Definitely.

>>The inherent lower terminal voltage and cell mAH capacity were the real
>>reasons.
>
> Agreed.

** No elaboration was needed.

> I'm rather mystified by the results.

** Bad science is no mystery.

..... Phil

== 1 of 3 ==
Date: Tues, May 31 2011 1:03 am
From: "N_Cook"

Smitty Two <prestwhich@earthlink.net> wrote in message
news:prestwhich-069B08.10540030052011@news.eternal-september.org...
> In article <is0gie$ncs$1@dont-email.me>, "N_Cook" <diverse@tcp.co.uk>
> wrote:
>
> > Vale <vale@fastwebnet.it> wrote in message
> > news:kWOEp.29095$GZ3.9073@tornado.fastwebnet.it...
> > > My expensive multimeter has got broken plastic pins that hold the lcd
> > disply
> > > on the pcb.
> > > In spite of all my efforts I can't correctly align the zebra contacts.
> > > Is there anybody willing to explain me how to do it?
> > > Thanks
> > >
> > >
> >
> >
> > Zebra contacts are self-aligning thats the point of them. Assuming
contacts
> > and zebra are clean and good and gap between pcb and LCD glass is
correct
> > then all should be well, at least one zebra contact should lie between
each
> > pcb pads and its corresponding lcd land
>
> With the alignment pins broken off, how do you suggest OP correctly
> positions the display WRT the PCB?

I assume some stubs or marks remain where the plastic pins broke off. Drill
and glue some replacement pins , as long as within half a land of true then
should line up

== 2 of 3 ==
Date: Tues, May 31 2011 8:36 am
From: Jeff Liebermann

On Mon, 30 May 2011 17:43:17 +0200, "Vale" <vale@fastwebnet.it> wrote:

>My expensive multimeter has got broken plastic pins that hold the lcd disply
>on the pcb.

Does your expensive multimeter have a manufacturer and model number?

>In spite of all my efforts I can't correctly align the zebra contacts.
>Is there anybody willing to explain me how to do it?

What does the display show? A few segments missing? A few digits
missing? Nothing perhaps?

You might align it visually. The problem is positioning the strip at
an angle, where the conductive parts of the Zebra strip will short two
adjacent contacts on either the display or the PCB. Without any means
to align the display and the PCB, that's quite a challenge. If the
Zebra strip is the same spacing as the display and PCB contacts, then
correct alignment is mandatory. However, if the spacing on the Zebra
strip is considerably smaller than the PCB and LCD spacing, then the
connector can tolerate considerable misalignment and still work.

There's also a question of how are you going to keep it aligned and
properly compressed with a broken mounting frame. Methinks your best
approach is to find the broken plastic pieces, and attempt to repair
the plastic frame first. Another approach would be to identify the
manufacturer of the mounting frame/pins/whatever, and obtain a
replacement. Lastly, if the multimeter is truly expensive and a
repair is justified, the manufacturer may have a repair/exchange
program.

Also, after many years, some elastometric and other rubber connectors
tend to leak whatever oil is used to keep the rubber flexible. When
connected, it's not a problem, but once moved, the oil film acts as an
insulator. Lightly clean both the PCB and LCD with alcohol to remove
any oil.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 3 of 3 ==
Date: Tues, May 31 2011 9:32 am
From: "Vale"

==============================================================================
TOPIC: Valves badged Orange , rebadged what make?
http://groups.google.com/group/sci.electronics.repair/t/b405f7894dddeac4?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, May 31 2011 1:10 am
From: "N_Cook"

The owner had lived with the "shaver" noise for months,but had gradually got
worse. Masked by the demand effect, no music - light buzz, high music
volume - loud buzz.
Absolutely quiet transformer now. Just hope the other end "E" does not play
up as that would require removing the Tx and its wiring from the chassis. It
is now tight up against the bobbin now so not too likely .

==============================================================================
TOPIC: WHAT IS ISLAM? ????????
http://groups.google.com/group/sci.electronics.repair/t/71561ac87a746849?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, May 31 2011 4:14 am
From: bv

WHAT IS ISLAM?

Can we find an explanation of the great universe? Is there any
convincing interpretation of the secret of existence? We realize that
no family can function properly without a responsible head, that no
city can prosperously exist without sound administration, and that no
state can survive without a leader of some kind. We also realize that
nothing comes into being on its own. Moreover, we observe that the
universe exists and functions in the most orderly manner, and that it
has survived for hundreds of thousand of years. Can we then say that
all this is accidental and haphazard? Can we attribute the existence
of man and the whole world to mere chance.
Man represents only a very small portion of the great universe. And if
he can make plans and appreciate the merits of planning, then his own
existence and the survival of the universe must also be a planned
policy. This means that there is an extraordinary power to bring
things into being and keep them moving in order.
In the world then must be a great force in action to keep everything
in order. In the beautiful nature there must be a Great creator who
creates the most charming pieces of art produces every thing for a
special purpose in life. The deeply enlightened people recognize this
creator and call him Allah "God". He is not a man because no man can
create or make another man. He is not an animal, nor he is a plant. He
is neither an Idol nor is He a statue of any kind because non of these
things can make itself or create anything else. He is different from
all these things because he is the maker and keeper of them all. The
maker of anything must be different from and greater than things which
he makes.
There are various ways to know God "ALLAH'' and there are many things
to tell about him. The great wonders and impressive marvels of the
world are like open books in which we can read about God. Besides, God
Himself comes to our aid through the many Messengers and revelations
He has sent down to man. These Messengers and revelations tell us
everything we need to know about God.
The complete acceptance of the teachings and guidance of God 'Allah'
as revealed to His Messengers Muhammad is the religion of Islam. Islam
enjoins faith in the oneness and sovereignty of Allah, which makes man
aware of meaningfulness of the Universe and of his place in it. This
belief frees him from all fears and superstitions by making him
conscious of the presence of the Almighty Allah and of man's
obligations towards Him. This faith must be expressed and tested in
actions, faith alone is not enough. Belief in one God requires that we
look upon all humanity as one family under the universal Omnipotence
of God the Creator and Nourisher of all. Islam rejects the idea of
chosen people, making belief in God and good actions the only way to
heaven. Thus, a direct relationship in established with God, without
any intercessor.
Islam is not a new religion. It is, in essence, the same message and
guidance which Allah revealed to all Prophets. Adam, Noah, Abraham,
Ismael, David, Moses and Jesus (PBUT). But the message which was
revealed to Prophet Mohammed (PBUT) is Islam in its comprehensive,
complete and final form.
The Quran is the last revealed word of Allah and the basic source of
Islamic teachings and laws. The Quran deals with the basis of creeds,
morality, history of humanity, worship, knowledge, wisdom, God-man
relationship, and human relationship in all aspects. Comprehensive
teaching on which, can be built sound systems of social justice,
economics, politics, legislation, jurisprudence, law and international
relations, are important contents of the Quran. Hadith, the teachings,
sayings and actions of Prophet Mohammed (PBUT), meticulously reported
and collected by his devoted companions. Explained and elaborated the
Quranic verses.
THE FUNDAMENTAL ARTICLES OF FAITH IN ISLAM
The true faithful Muslim believes in the following Principal articles
of faith:-
1. He believes in One God 'Allah', Supreme and Eternal, Infinite and
Mighty, Merciful and Compassionate, Creator and Provider.
2. He believes in all Messengers of God without any discrimination
among them. Every known nation had a warner or Messenger from God.
They were chosen by God to teach mankind and deliver His divine
message. The Quran mentions the name of twenty five of them. Among
them Mohammad stands as the last Messenger and the crowning glory of
the foundation of Prophethood.
3. Muslin believes in all scriptures and revelations of God. They were
the guiding light which the Messengers received to show their
respected peoples the Right Path of God. In the Quran a special
reference is made to the books of Abraham, Moses, David and Jesus. But
long before the revelations has been lost or corrupted. The only
authentic and complete book of God in existence in the Quran.
4. The true Muslim believes in the Angels of Allah. They are purely
spiritual and splendid beings whose nature requires no0061 Z food,
drink or sleep. They spend their days and nights in the worship of
God.
5. Muslim believes in the last Day of Judgement. This world will come
to an end someday, and the dead will rise to stand for their final and
fair trial. People with good records will be generously, rewarded and
warmly welcomed to the Heaven of Allah, and those with bad records
will be punished and cast into Hell.
6. Muslim believes in the timeless knowledge of God and His power to
plan and execute His planes and nothing could happen in His Kingdom
against His will. His knowledge and power are in action at all times
and command over His creation. He is wise and merciful, and whatever
He does must have a meaningful purpose. If this is established in our
mind and hearts, we should accept with good faith all that He does,
although we may fail to under stand it fully, or think it is bad.
THE FIVE PILLARS OF ISLAM
Faith without actions arid practice is a dead end, as far as Islam is
concerned. Faith by nature is very sensitive and can be most
effective. When it is not out of practice or out of use, it quickly
loses its liveliness and motivation power.
There are five pillars of Islam:
1 - The declaration of faith: To bear witness that there is none
worthy of worship except Allah, and that Mohammad (PBUH) is His
Messenger to all human beings till the Day of Judgment. The
Prophethood of Mohammad obliges the Muslims to follow, His exemplary
life as a model.
2 - Prayers: Daily, prayers are offered five times a day as a duty
towards Allah. They strengthen and enliven the belief in Allah and
inspire man to a higher morality. They purity the heart and prevent
temptation towards wrong - doings and evil.
3 - Fasting the month of Ramadan. The Muslims during the month of
Ramadan not only abstain from food, drink and sexual intercourse from
dawn to sunset but also sincerity and devotion. It develops a sound
social conscience, patience, unselfishness and will - Power.
4 - Zakkah: The literal and simple meaning of Zakkah is charity. The
technical meaning of this word designates the annual amount in kind or
coin which a Muslim with means must distribute among the rightful
beneficiaries. But the religious and spiritual significance of Zakkah
is much deeper and more lively. So it has humanitarian and
sociopolitical values.
5 - Hajj (Pilgrimage to Makkah): It is to be performed once in a
lifetime, if one can afford it financially and physically.

If you wish to know more about Islam, we prefer to visit the following
websites:

http://www.islam-guide.com

http://www.islamhouse.com/s/9661

http://www.todayislam.com

http://www.thekeytoislam.com

http://www.islamland.com

http://www.discoverislam.com

http://www.thetruereligion.org

http://www.beconvinced.com

http://islamtomorrow.com

http://www.thisistruth.org

http://www.quran-m.com/firas/en1

http://kaheel7.com/eng

http://www.usc.edu/dept/MSA/quran

http://www.quranforall.org

http://www.quranexplorer.com/quran

http://www.knowmuhammad.com

http://www.rasoulallah.net/v2/index.aspx?lang=e

http://www.prophetmuhammed.org

http://www.chatislamonline.org/ar

http://www.dar-us-salam.com

http://youtubeislam.com

== 1 of 16 ==
Date: Tues, May 31 2011 4:41 am
From: Man-wai Chang

How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
slow-brown one?

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39
^ ^ 19:36:01 up 6 days 4:38 0 users load average: 1.22 1.09 1.06
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

== 2 of 16 ==
Date: Tues, May 31 2011 5:07 am
From: "Phil Allison"

"Man-wai Chang"
>
> How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
> slow-brown one?

** Confucius once say:

" The quick brown fox jumps over the lazy dog "

Think about it ...........

.... Phil

== 3 of 16 ==
Date: Tues, May 31 2011 5:47 am
From: Globemaker

On May 31, 7:41 am, Man-wai Chang <toylet.toy...@gmail.com> wrote:
> How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
> slow-brown one?
>
> --
> @~@ Might, Courage, Vision, SINCERITY.
> / v \ Simplicity is Beauty! May the Force and farces be with you!
> /( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39
> ^ ^ 19:36:01 up 6 days 4:38 0 users load average: 1.22 1.09 1.06
> 不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

The danger, on a scale from 1 to 10 is 8. Some equipment can be
damaged in a millisecond, so a slow-blown fuse can result in a ruined
piece of equipment. For example, an integrated circuit could need 12
volts, but you plug in the wrong wall wart that has no labels on it.
It has 18 volts instead of 12 volts, but it uses the same diameter
coaxial connector. A fast fuse protects in 400 microseconds, but the
slow blow does not blow that fast so the 45 nanometer digital device
gets melted in 1000 microseconds.

== 4 of 16 ==
Date: Tues, May 31 2011 6:54 am
From: "Phil Allison"

"Globemaker"

** Globemaker is one of those personages who sincerely believes that " Star
Trek " is a documentary.

And he has pointy ears too.

Beam me up Scotty ........

... Phil

== 5 of 16 ==
Date: Tues, May 31 2011 8:44 am
From: Tim Wescott

On 05/31/2011 04:41 AM, Man-wai Chang wrote:
>
> How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
> slow-brown one?

It depends entirely on the equipment. Slow-blow fuses used to be more
expensive than fast-blow fuses, and tend to be less available. So a
designer's knee-jerk reaction may be to specify a fast-blow fuse
'because it's there'.

So there's a good chance that you can drop your slow-blow fuse in there
and everything will be fine, but if you do and burn something up, don't
come crying to me. I would hesitate to do so myself unless I knew what
was in the product, and felt that a slow-blow would work OK. I would
also hesitate to replace the fuse unless I knew why the original had
blown -- fuses blow for reasons, and if the equipment is dorked and
blowing fuses, then putting in more fuses will just make it more dorked.

Your best bet is to get the right fuse, and at least try to fix the
fault before you turn the equipment on with your shiny new fuse.

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 6 of 16 ==
Date: Tues, May 31 2011 8:57 am
From: Man-wai Chang

> Your best bet is to get the right fuse, and at least try to fix the
> fault before you turn the equipment on with your shiny new fuse.

For a multimeter, is it always better to use a fast blow fuse?

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39
^ ^ 23:56:02 up 6 days 8:58 0 users load average: 1.05 1.09 1.06
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

== 7 of 16 ==
Date: Tues, May 31 2011 8:57 am
From: Man-wai Chang

> It has 18 volts instead of 12 volts, but it uses the same diameter
> coaxial connector. A fast fuse protects in 400 microseconds, but the
> slow blow does not blow that fast so the 45 nanometer digital device
> gets melted in 1000 microseconds.

Is the 13A BS1362 fuse a fast blow one?

== 8 of 16 ==
Date: Tues, May 31 2011 9:01 am
From: Tim Wescott

It depends on the multimeter. I'd stick with the fast blow fuse and
stop putting it in 'voltage' mode when you've got it connected to
measure current.

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 9 of 16 ==
Date: Tues, May 31 2011 9:02 am
From: Tim Wescott

On 05/31/2011 08:57 AM, Man-wai Chang wrote:
>> Your best bet is to get the right fuse, and at least try to fix the
>> fault before you turn the equipment on with your shiny new fuse.
>
> For a multimeter, is it always better to use a fast blow fuse?
>
Check to make sure that the fuse isn't being used as the current shunt
-- if it is, then you don't just need the right current rating, you need
a matched fuse.

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 10 of 16 ==
Date: Tues, May 31 2011 9:40 am
From: Man-wai Chang

> It depends on the multimeter. I'd stick with the fast blow fuse and stop
> putting it in 'voltage' mode when you've got it connected to measure
> current.

It's a glass one, 500mA fast blow according to the manual.

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39
^ ^ 00:36:01 up 6 days 9:38 0 users load average: 1.12 1.09 1.12
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

== 11 of 16 ==
Date: Tues, May 31 2011 9:51 am
From: Jeff Liebermann

On Tue, 31 May 2011 09:02:08 -0700, Tim Wescott <tim@seemywebsite.com>
wrote:

>On 05/31/2011 08:57 AM, Man-wai Chang wrote:
>>> Your best bet is to get the right fuse, and at least try to fix the
>>> fault before you turn the equipment on with your shiny new fuse.
>>
>> For a multimeter, is it always better to use a fast blow fuse?

>Check to make sure that the fuse isn't being used as the current shunt
>-- if it is, then you don't just need the right current rating, you need
>a matched fuse.

Chuckle. If a fuse were used as a current shunt, then when the fuse
blows, instead of a few millivolts across the fuse, the meter now gets
the full voltage of whatever is being measured. The fuse holder
contact resistance will probably be larger than the wire resistance in
the fuse (fast blow). I don't think anyone uses a fuse as a current
shunt.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 12 of 16 ==
Date: Tues, May 31 2011 9:54 am
From: Jeff Liebermann

On Tue, 31 May 2011 23:57:58 +0800, Man-wai Chang
<toylet.toylet@gmail.com> wrote:

That's the number of the plug, not the fuse:
<http://en.wikipedia.org/wiki/BS_1363>
It does have a fuse inside, but I don't know the value or type.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 13 of 16 ==
Date: Tues, May 31 2011 10:16 am
From: Winston

Tim Wescott wrote:
> On 05/31/2011 08:57 AM, Man-wai Chang wrote:
>>> Your best bet is to get the right fuse, and at least try to fix the
>>> fault before you turn the equipment on with your shiny new fuse.
>>
>> For a multimeter, is it always better to use a fast blow fuse?
>
> It depends on the multimeter. I'd stick with the fast blow fuse and stop
> putting it in 'voltage' mode when you've got it connected to measure
> current.

That's 'current' mode when you've got it connected to measure
voltage, yes?

--Winston

== 14 of 16 ==
Date: Tues, May 31 2011 11:07 am
From: Tim Wescott

On 05/31/2011 10:16 AM, Winston wrote:
> Tim Wescott wrote:
>> On 05/31/2011 08:57 AM, Man-wai Chang wrote:
>>>> Your best bet is to get the right fuse, and at least try to fix the
>>>> fault before you turn the equipment on with your shiny new fuse.
>>>
>>> For a multimeter, is it always better to use a fast blow fuse?
>>
>> It depends on the multimeter. I'd stick with the fast blow fuse and stop
>> putting it in 'voltage' mode when you've got it connected to measure
>> current.
>
> That's 'current' mode when you've got it connected to measure
> voltage, yes?

Uhhh...

D'oh!

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 15 of 16 ==
Date: Tues, May 31 2011 11:44 am
From: Jamie

Man-wai Chang wrote:

>> Your best bet is to get the right fuse, and at least try to fix the
>> fault before you turn the equipment on with your shiny new fuse.
>
>
> For a multimeter, is it always better to use a fast blow fuse?
>
yes

== 16 of 16 ==
Date: Tues, May 31 2011 11:47 am
From: Jamie

Jeff Liebermann wrote:

Jamie

== 1 of 3 ==
Date: Tues, May 31 2011 9:47 am
From: myfathersson

The power has completely gone off and it is still plugged in. I cant
see any fuse on the back but does anyone know if there is one on the
power supply inside please?

I found a page where they SAY they have a service manual to down load
at http://www.eserviceinfo.com/downloadsm/148/Samsung_SV-4000W.html
but where it says NOW DOWNLOADING, nothing seems to download.

I can search on their Samsung page at http://www.eserviceinfo.com/equipment_mfg/Samsung_4.html
but there doesnt seem to be an appropriate one there? Does anyone here
know how to navigate their site?

== 2 of 3 ==
Date: Tues, May 31 2011 10:16 am
From: myfathersson

Sorry, let me re-phrase that: DOWNLOADING NOW means you have to click
on some virtually hidden link two thirds down on the page to download

Doing that downloads something called a .djvu file. which requires
installing Nuance Software .pdf reader.

When you do that, it just tells you that it cant open the mysterious
286kb sv4000w.djvu file you have just downloaded!

== 3 of 3 ==
Date: Tues, May 31 2011 10:43 am
From: myfathersson

Sorry, let me re-phrase that: DOWNLOADING NOW means you have to click
on some virtually hidden link two thirds down on the page to download

Doing that downloads something called a .djvu file. which requires
installing Nuance Software .pdf reader.

When you do that, it just tells you that it cant open the mysterious
286kb sv4000w.djvu file you have just downloaded!

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sci.electronics.repair - 11 new messages in 3 topics - digest

12:40 AM Penedão 0 comments

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

* Power transistor question... - 6 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/48e3a91c572ef00c?hl=en
* Wall Warts - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/de407a5056a54ee0?hl=en
* NiMH new battery conditioning - 4 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/642feb09361f607e?hl=en

== 1 of 6 ==
Date: Mon, May 30 2011 6:16 pm
From: "Phil Allison"

"Jeff Liebermann"
"Phil Allison"
>
> The problem with the Extech 380193 Handheld LCR meter is that it will
> measure ESR at 120Hz and 1KHz. ESR is usually measured at about
> 100KHz. Dave Jones mentions this at about 12-13 minutes into his
> video. This is because electrolytic cazapitors exhibit a minimum ESR
> around 100Khz.
> <http://www.amccaps.com/leaded-capacitors/switch-mode-ceramic-capacitors/esr-vs-frequency.html>

** Gotta pick you up on this one !!

That link shows ESR curves with frequency of a couple of * CERAMIC *
capacitors of unusually high values.

ESR meters intended for in circuit testing of electros by service techs
simply measure the cap's IMPEDANCE at around 100kHz. At this frequency -
all but the lowest value electros have their minimum impedances and the
values obtained are very close to ESR values at the same frequency. This
allows one to compare electros for (high frequency) ESR and pick out faulty
examples very easily.

OTOH, the Extech meter is designed to measure L and C values for a wide
range of inductors and capacitors and uses to standard test frequency of
1kHz as used in countless other instruments. This means it is NOT intended
to perform in-circuit testing of L and C value as other circuitry that may
be in parallel may spoil the readings.

However, in the case of electros with values from say 4.7 uF and upwards and
fitted to a TV set I would expect readings to be OK and the ESR values
obtained to be useable. It would be a good idea to re-test any electros
that are removed cos the ESR reading seemed high.

IMO - the 120 Hz frequency should only be used for out of circuit testing.

..... Phil

== 2 of 6 ==
Date: Mon, May 30 2011 7:17 pm
From: "Phil Allison"

"Meat Plow"

>> http://www.youtube.com/watch?v=zEA5MfllPdg
>
> Not a bad little meter for the $$$$. Anyone who does work on consumer
> electronics ought to have one or something similar. Removes a lot of
> guess work.

** I disagree.

An LCR meter is more useful for design and production than in servicing.

Many low cost DMMs include capacitance ranges that can measure from a few pF
up to 200 or 2000uF.

A dedicated ESR meter handles electros just fine while in circuit - and
lets you test all kinds of cells too, which an LCR meter often cannot.

Any DMM can read the resistance of an inductor or transformer winding.

The only function left is to measure inductors for value.

.... Phil

== 3 of 6 ==
Date: Mon, May 30 2011 7:29 pm
From: Jeff Liebermann

On Tue, 31 May 2011 11:16:04 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>> The problem with the Extech 380193 Handheld LCR meter is that it will
>> measure ESR at 120Hz and 1KHz. ESR is usually measured at about
>> 100KHz. Dave Jones mentions this at about 12-13 minutes into his
>> video. This is because electrolytic cazapitors exhibit a minimum ESR
>> around 100Khz.
>> <http://www.amccaps.com/leaded-capacitors/switch-mode-ceramic-capacitors/esr-vs-frequency.html>

>That link shows ESR curves with frequency of a couple of * CERAMIC *
>capacitors of unusually high values.

Oops, y'er right. Sorry(tm).

Oddly, while the ESR of the ceramic caps are much lower than
electrolytics, the curve shapes seem to be similar.

Googling, I find:
<http://www.low-esr.com/esrfreqperfcurves.asp>
Note the dip in ESR and loss tangent at around 100KHz on various
graphs.

>ESR meters intended for in circuit testing of electros by service techs
>simply measure the cap's IMPEDANCE at around 100kHz. At this frequency -
>all but the lowest value electros have their minimum impedances and the
>values obtained are very close to ESR values at the same frequency. This
>allows one to compare electros for (high frequency) ESR and pick out faulty
>examples very easily.
>
>OTOH, the Extech meter is designed to measure L and C values for a wide
>range of inductors and capacitors and uses to standard test frequency of
>1kHz as used in countless other instruments. This means it is NOT intended
>to perform in-circuit testing of L and C value as other circuitry that may
>be in parallel may spoil the readings.
>
>However, in the case of electros with values from say 4.7 uF and upwards and
>fitted to a TV set I would expect readings to be OK and the ESR values
>obtained to be useable. It would be a good idea to re-test any electros
>that are removed cos the ESR reading seemed high.
>
>IMO - the 120 Hz frequency should only be used for out of circuit testing.

Yep. Agreed on all points.

>..... Phil

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 4 of 6 ==
Date: Mon, May 30 2011 8:31 pm
From: "Phil Allison"

"Jeff Liebermann"
"Phil Allison"
>
>>That link shows ESR curves with frequency of a couple of * CERAMIC *
>>capacitors of unusually high values.
>
> Oops, y'er right. Sorry(tm).
>
> Oddly, while the ESR of the ceramic caps are much lower than
> electrolytics, the curve shapes seem to be similar.
>
> Googling, I find:
> <http://www.low-esr.com/esrfreqperfcurves.asp>
> Note the dip in ESR and loss tangent at around 100KHz on various
> graphs.

** I see no such trend for the electros.

The ESR of most electros is almost constant down to about 500Hz, then rises
to a few times its high frequency value at 50Hz. I believe mobility of the
ions in the electrolyte is the cause.

Electros uniquely have very low Q factors - which means their impedance *
stays low * over a very wide frequency range.

A typical 470uF electro has an impedance under 0.1 ohms from 4kHz to 1MHz as
does the 330uF example in the graphs.

High Q capacitors ( film and ceramic) all have sharp impedance dips at self
resonance.

.... Phil

== 5 of 6 ==
Date: Mon, May 30 2011 8:46 pm
From: "Dave"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:94j1ebFms1U1@mid.individual.net...
>
> "Meat Plow"
>
>>> http://www.youtube.com/watch?v=zEA5MfllPdg
>>
>> Not a bad little meter for the $$$$. Anyone who does work on consumer
>> electronics ought to have one or something similar. Removes a lot of
>> guess work.
>
>
> ** I disagree.
>
> An LCR meter is more useful for design and production than in servicing.
>
> Many low cost DMMs include capacitance ranges that can measure from a few
> pF up to 200 or 2000uF.
>
> A dedicated ESR meter handles electros just fine while in circuit - and
> lets you test all kinds of cells too, which an LCR meter often cannot.
>
> Any DMM can read the resistance of an inductor or transformer winding.
>
> The only function left is to measure inductors for value.
>
>
> .... Phil
>

Wanted to thank *everyone* for the info and encouragement I have received in
this discussion. Bottom line for me, at least for now, is simply don't test
in-circuit (pop one lead and then test after discharging). Have also found
a ton of material on youtube and the net that convinces me to get a
dedicated ESR meter (or possibly build one.) Anyway, thanks all for a very
enlightening discussion.

Take it easy...

Dave

== 6 of 6 ==
Date: Mon, May 30 2011 8:52 pm
From: "Phil Allison"

"Dave"
>
> Wanted to thank *everyone* for the info and encouragement I have received
> in this discussion. Bottom line for me, at least for now, is simply don't
> test in-circuit (pop one lead and then test after discharging). Have also
> found a ton of material on youtube and the net that convinces me to get a
> dedicated ESR meter (or possibly build one.) Anyway, thanks all for a
> very enlightening discussion.

** This is the one I would buy - if I did not already have two of Bob's
earlier designs.

http://www.anatekcorp.com/blueesr.htm

BTW

Bob is an old mate of mine.

.... Phil

==============================================================================
TOPIC: Wall Warts
http://groups.google.com/group/sci.electronics.repair/t/de407a5056a54ee0?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, May 30 2011 6:18 pm
From: Jeff Liebermann

On Mon, 30 May 2011 15:14:17 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

>"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
>news:a4u7u69f03pb04a2o3j3jjbdh9msv9r4ih@4ax.com...
>
>> I also use NiMH batteries in my various cameras (Canon S5IS etc) all
>> of which use AA cells. I'm seeing the typical 1%/day self-discharge
>> rate. I keep two sets of batteries in the bag. It's not unusual for
>> me to find the spares to be nearly dead after about 2 months.
>
>> Your NiMH milage may vary, but mine sucks.
>
>Weird. Which brands do you use? I use mostly MAHA (PowerEx).

Yeah, I know I'm weird. I use a random assortment of whatever I
blunder across. Costco has Sanyo Eneloop, so I have a pile of those.
I just found several 4 packs of Energizer 2300ma-hr NiMH cells, so I
guess I'll use those. I have no idea what's in the camera or in the
bottom of the bag, but I'll guess is some no-name brand I picked up at
a ham radio flea market. I just found some Duracel 2050ma-hr cells.
Oh swell, a pair of Lenmar NoMem Pro 1500 ma-hr cells in my emergency
bag. Nice mess (and proud of it).

I've been running some battery tests on the new batteries for the last
4 hrs to see if I can find any "conditioning" effects. Stay tunes.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 1 of 4 ==
Date: Mon, May 30 2011 9:18 pm
From: Jeff Liebermann

Per a previous discussion, I decided to test whether new NiMH
batteries need to be conditioned or charged several times before
reaching their rated capacity. Apparently they do.

The test setup is a West Mtn Radio CBA-IIv1 battery analyzer.
<http://802.11junk.com/jeffl/NiMH/cba-II.jpg>
I didn't want to wait 20 hrs per test to get the official rated
capacity, so I elected to run the tests at 1C which resulted in about
a 45 minute test, but also resulted in a much lower capacity result.
It also caused some unexpected errors. The design of the CBA-II does
not include a Kelvin probe connection to eliminate any losses in the
cables and connectors. It measures the voltage at the load, instead
of at the battery. This is not a problem at low load currents, but at
2 amps, results in considerable error.

Two new (out of the package) batteries were used. An Energizer NiMH
2300 ma-hr cell, and a Duracell 2050 ma-hr cell. Between tests, the
batteries were quick charged in a Radio Shack 23-1305 NiMH quick
charger (15 min). Each battery was discharged 3 times and the
discharge curves plotted.

Note that the Energizer package says 2450 ma-hr, while the battery is
marked 2300 ma-hrs.
<http://802.11junk.com/jeffl/NiMH/energizer.jpg>

The Energizer cell showed no change in capacity between discharges.
<http://802.11junk.com/jeffl/NiMH/Energizer-NiMH-2300.jpg>
Using 1.0VDC as the end point, the measured cell capacity is:
Run 1 1785 ma-hr
Run 2 1890 ma-hr
Run 3 1895 ma-hr

The Duracell cell showed a larger change.
<http://802.11junk.com/jeffl/NiMH/Duracelll-NiMH-2050.jpg>
Using 1.0VDC as the end point, the measured cell capacity is:
Run 1 1200 ma-hr
Run 2 1270 ma-hr
Run 3 1385 ma-hr

The net improvement over 3 charge-discharge runs is about 10% for the
Energizer and 15% for the Duracell. Not huge, but certainly
measurable. Whether it is worth the effort conditioning the battery
before use, is debatable.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 2 of 4 ==
Date: Mon, May 30 2011 9:37 pm
From: "Phil Allison"

"Jeff Liebermann"
>
> Per a previous discussion, I decided to test whether new NiMH
> batteries need to be conditioned or charged several times before
> reaching their rated capacity. Apparently they do.
>
> The test setup is a West Mtn Radio CBA-IIv1 battery analyzer.
> <http://802.11junk.com/jeffl/NiMH/cba-II.jpg>
> I didn't want to wait 20 hrs per test to get the official rated
> capacity, so I elected to run the tests at 1C which resulted in about
> a 45 minute test, but also resulted in a much lower capacity result.
> It also caused some unexpected errors. The design of the CBA-II does
> not include a Kelvin probe connection to eliminate any losses in the
> cables and connectors. It measures the voltage at the load, instead
> of at the battery. This is not a problem at low load currents, but at
> 2 amps, results in considerable error.
>
> Two new (out of the package) batteries were used. An Energizer NiMH
> 2300 ma-hr cell, and a Duracell 2050 ma-hr cell. Between tests, the
> batteries were quick charged in a Radio Shack 23-1305 NiMH quick
> charger (15 min). Each battery was discharged 3 times and the
> discharge curves plotted.
>
> Note that the Energizer package says 2450 ma-hr, while the battery is
> marked 2300 ma-hrs.
> <http://802.11junk.com/jeffl/NiMH/energizer.jpg>
>
> The Energizer cell showed no change in capacity between discharges.
> <http://802.11junk.com/jeffl/NiMH/Energizer-NiMH-2300.jpg>
> Using 1.0VDC as the end point, the measured cell capacity is:
> Run 1 1785 ma-hr
> Run 2 1890 ma-hr
> Run 3 1895 ma-hr
>
> The Duracell cell showed a larger change.
> <http://802.11junk.com/jeffl/NiMH/Duracelll-NiMH-2050.jpg>
> Using 1.0VDC as the end point, the measured cell capacity is:
> Run 1 1200 ma-hr
> Run 2 1270 ma-hr
> Run 3 1385 ma-hr
>
> The net improvement over 3 charge-discharge runs is about 10% for the
> Energizer and 15% for the Duracell. Not huge, but certainly
> measurable. Whether it is worth the effort conditioning the battery
> before use, is debatable.

** You got something against NiMh cells ?

I would never mistreat NiMH AA cells the way you just have.

15 minute charging is absurd for any cell NOT designed for such abuse - it
causes overheating with new cells and destruction of older ones.

A 1C discharge test will never give the rated capacity figure with NiCd or
NiMH.

IME - the idea that new cells have a "running in "period is a MYTH
invented by retailers back in the 1970s when consumers were first sold AA
and C size NiCds and found their performance disappointing when compared to
alkalines.

The inherent lower terminal voltage and cell mAH capacity were the real
reasons.

.... Phil

== 3 of 4 ==
Date: Mon, May 30 2011 10:38 pm
From: Jeff Liebermann

On Tue, 31 May 2011 14:37:43 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>** You got something against NiMh cells ?

Yep. I don't like them.

>I would never mistreat NiMH AA cells the way you just have.

I didn't have time to do it the right way (20 hr discharge). I can do
it again with a longer discharge time and lower current. I still have
several of both brand of cells that I haven't mistreated yet. However,
it will take about a week to produce results (plus dragging home a
spare computah to do the test and building a better battery holder).

>15 minute charging is absurd for any cell NOT designed for such abuse - it
>causes overheating with new cells and destruction of older ones.

True for the Duracell, which recommends 205ma for 15 hrs to recharge
printed on the cell. The Energizer Recharge battery doesn't specify a
charge current:
<http://data.energizer.com/PDFs/nh15-2000.pdf>
However, the recommended battery charger is a quick charger:
<http://data.energizer.com/PDFs/ch15mn2.pdf>
with a 15 minute charge time.

I've been testing batteries since about 2005 while working on a
product that I won't discuss. However, I will point out that many
NiCd batteries can be quick charged at ridiculously high rates, as
long as certain (unspecified) conditions are met. If you don't mind,
I'll leave this unsubstantiated.

Incidentally, the Sanyo ENELOOP battery data sheet recommends fast
charging at 2A for 1.1 hrs:
<http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>

>A 1C discharge test will never give the rated capacity figure with NiCd or
>NiMH.

I indicated that in my posting as:

> I didn't want to wait 20 hrs per test to get the official rated
> capacity, so I elected to run the tests at 1C which resulted in about
> a 45 minute test, but also resulted in a much lower capacity result.

The purpose of the test was to see if a brand new battery required
several charge-discharge cycles before it would deliver full capacity,
not to measure the actual rated capacity in a 20 hr discharge test.

>IME - the idea that new cells have a "running in "period is a MYTH
>invented by retailers back in the 1970s when consumers were first sold AA
>and C size NiCds and found their performance disappointing when compared to
>alkalines.

Maybe. There was also quite a bit of effort in the mid 1990's by
manufactures to differentiate their NiMH products from NiCd. For
example, I found a pair of Lenmar NoMEM Pro NiMH batteries, which are
an obvious shot at the alleged NiCd "memory effect". Another
possibility is that some support droid needed a line to get rid of a
complaining customer and invented the "conditioning" for the purpose.

>The inherent lower terminal voltage and cell mAH capacity were the real
>reasons.

Agreed. I went through the mess with alleged "9V" (6 cell) NiCd
batteries, being more like 7.2VDC. With a nominal operating voltage
for 1.2 to 1.3 VDC for NiCd and NiMH, anything designed for a 1.5VDC
alkaline is going to have a problem.

Incidentally, all of the marine radios I helped design were required
to function down to 10.0VDC applied power. They couldn't reach rated
TX power at 70% of rated voltage, but still had to belch at least a
few watts of RF and remain functional.

I'm rather mystified by the results. Although the improvement in
capacity after 3 charge-discharge cycles is minor (10-15%), it still
seems for real. My previous tests didn't show such an increase in
capacity. Instead, it showed a deterioration in capacity. However, I
was testing for something quite different, and was working with a mix
of old and new cells.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

== 4 of 4 ==
Date: Mon, May 30 2011 10:57 pm
From: "Phil Allison"

"Jeff Liebermann"
>
>>** You got something against NiMh cells ?
>
> Yep. I don't like them.

** Wanker.

>>I would never mistreat NiMH AA cells the way you just have.
>
> I didn't have time to do it the right way (20 hr discharge).

** The 15 min charging was the abuse - fool.

> I can do
> it again with a longer discharge time and lower current.

** The 15 min charging was the abuse - fool.

>>15 minute charging is absurd for any cell NOT designed for such abuse - it
>>causes overheating with new cells and destruction of older ones.
>
> True for the Duracell,

** True for all of them - fool.

> However, the recommended battery charger is a quick charger:
> <http://data.energizer.com/PDFs/ch15mn2.pdf>
> with a 15 minute charge time.

** They would - since they sell the fucking things.

Energiser sell a whole range of chargers designed to destroy NiMh cells.

Means they sell more cells.

> I've been testing batteries since about 2005

** I've been doing it since 1979.

> However, I will point out that many
> NiCd batteries can be quick charged at ridiculously high rates,

** Only a rare few, specially designed NiCds were designed for it -
Sanyo's red " F " cells being one.

The issue is the HIGH probability of OVERCHARGING and hence over heating
with consequent internal damage.

> Incidentally, the Sanyo ENELOOP battery data sheet recommends fast
> charging at 2A for 1.1 hrs:
> <http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>

** Got nothing to do with a 15 minute charge in a cheap POS charger like you
did.

** Will you admit to being a raving lunatic ???

And save me the trouble of demonstrating it to the world over and over.

** Definitely.

>>The inherent lower terminal voltage and cell mAH capacity were the real
>>reasons.
>
> Agreed.

** No elaboration was needed.

> I'm rather mystified by the results.

** Bad science is no mystery.

..... Phil

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