sci.electronics.repair@googlegroups.com

Today's topics:

* Power transistor question... - 5 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/48e3a91c572ef00c?hl=en
* how to disassemble this AC Adapter? - 5 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/79c2e64c02b38c5d?hl=en
* zebra connector - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/22ac512ae9f1d16c?hl=en
* Wall Warts - 10 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/de407a5056a54ee0?hl=en
* microwave oven stopping prematurely, repairable? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/a4366967d76451a5?hl=en
* free shipping wholesale CLOTHING jacket T-shirt long sleeve suit and hoody(
Franklin Marshall,Monclereiderdown,nike,adidas,a&f,d&g,ed harday,bape,bbc,lv,
gucci,armani,polo, poul smith and so on)/http://www.24hours-online.com/ - 1
messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/531daf8b11ca41f0?hl=en

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

== 1 of 5 ==
Date: Mon, May 30 2011 12:38 am
From: "Dave"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:94g5a0FfaiU1@mid.individual.net...
>
> "Dave"
>
>> Now believe I already have an ESR meter, though I didn't realize that was
>> one of its functions. What I have is an Extech 380193 LCR meter, which
>> tells me that a fairly new but run of the mill 1uF electrolytic cap out
>> of my junkbox has 12.5 Ohms of resistance. If I were to try to use this
>> to measure the caps in-circuit, how should I proceed? I am guessing that
>> discharging the cap before touching my test leads to the solder pads
>> would give me a reading, but I really hesitate to do this without some
>> sort of suggestion that such is a safe proceedure for my meter. Am
>> guessing that readings in the single digits indicate a defective device.
>> Does this sound reasonable? No power to the circuit under test, of
>> course, and likely will push in the power button a few minutes before
>> beginning. Again, any advice is appreciated.
>
> ** Seen this ??
>
> http://www.youtube.com/watch?v=zEA5MfllPdg
>
> All you need to do is compare the ESR reading of a known good electro of
> about the same ratings and size with the one under test. If the one under
> test has say 5 times more ESR - it is useless or about to fail.
>
> Often, with worn out electros, the ESR may be over 100 ohms.
>
>
> .... Phil
>

No, I haven't seen that before. *Thank you.* Need to check and see if they
have any others I could use. Am continually amazed by what I find available
on youtube.

Is there anything special you know about testing a cap in-circuit with a
meter like this? Am still a little worried about maybe damaging my LCR
meter. It was a Christmas/Anniversary/Birthday gift from my loving wife
some 8 or 10 years ago, and would like to keep it in good working order.
Can't tell you how much I appreciate your help thus far with the subject at
hand...

Thanks again.

Dave

== 2 of 5 ==
Date: Mon, May 30 2011 3:09 am
From: "Phil Allison"

"Dave"

> Is there anything special you know about testing a cap in-circuit with a
> meter like this? Am still a little worried about maybe damaging my LCR
> meter.

** Just make sure the electros are discharged - short them if in any doubt.

.... Phil

== 3 of 5 ==
Date: Mon, May 30 2011 7:03 am
From: "David"

"Phil Allison" wrote in message
news:94h8neF4dgU1@mid.individual.net...

"Dave"
> Is there anything special you know about testing a cap
> in-circuit with a meter like this? Am still a little worried
> about maybe damaging my LCR meter.

** Just make sure the electros are discharged - short them if in
any doubt

.... Phil

***
The meter being damaged is not a problem if things are
discharged. The other issue is will this meter give accurate
in-circuit readings? ESR meters use a very low AC voltage of
typically 100 mV, a frequency of 100 KHz or so, and a very low
source impedance to make the test. This minimizes the influence
of other circuitry in parallel with the capacitor on the
measurement. If your meter uses a higher voltage or places DC
bias across the capacitor, in-circuit test results may not be
accurate.

David

== 4 of 5 ==
Date: Mon, May 30 2011 8:03 am
From: Jeff Liebermann

On Mon, 30 May 2011 10:05:12 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>** Seen this ??
>http://www.youtube.com/watch?v=zEA5MfllPdg

Kills 9V batteries. Otherwise, good price and good unit with many
features that I'll never use.

>All you need to do is compare the ESR reading of a known good electro of
>about the same ratings and size with the one under test. If the one under
>test has say 5 times more ESR - it is useless or about to fail.
>
>Often, with worn out electros, the ESR may be over 100 ohms.

That will work, if you happen to have a known good and identical
capacitor handy. I have a fair collection of electroltyics but not
every value and voltage.

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>

--
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

== 5 of 5 ==
Date: Mon, May 30 2011 2:50 pm
From: Meat Plow

On Mon, 30 May 2011 10:05:12 +1000, Phil Allison wrote:

> "Dave"
>
>> Now believe I already have an ESR meter, though I didn't realize that
>> was one of its functions. What I have is an Extech 380193 LCR meter,
>> which tells me that a fairly new but run of the mill 1uF electrolytic
>> cap out of my junkbox has 12.5 Ohms of resistance. If I were to try to
>> use this to measure the caps in-circuit, how should I proceed? I am
>> guessing that discharging the cap before touching my test leads to the
>> solder pads would give me a reading, but I really hesitate to do this
>> without some sort of suggestion that such is a safe proceedure for my
>> meter. Am guessing that readings in the single digits indicate a
>> defective device. Does this sound reasonable? No power to the circuit
>> under test, of course, and likely will push in the power button a few
>> minutes before beginning. Again, any advice is appreciated.
>
> ** Seen this ??
>
> http://www.youtube.com/watch?v=zEA5MfllPdg
>
> All you need to do is compare the ESR reading of a known good electro of
> about the same ratings and size with the one under test. If the one
> under test has say 5 times more ESR - it is useless or about to fail.
>
> Often, with worn out electros, the ESR may be over 100 ohms.
>
>
> .... Phil

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.

--
Live Fast Die Young, Leave A Pretty Corpse

==============================================================================
TOPIC: how to disassemble this AC Adapter?
http://groups.google.com/group/sci.electronics.repair/t/79c2e64c02b38c5d?hl=en
==============================================================================

== 1 of 5 ==
Date: Mon, May 30 2011 1:08 am
From: "N_Cook"

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:cfu5u6p8c4ihqo24eqbeggnhvqq0kgsa48@4ax.com...
> On Sun, 29 May 2011 20:21:40 +0100, "N_Cook" <diverse@tcp.co.uk>
> wrote:
>
> >First is to remove any sticky labels that may cover a securing screw.
>
> Good idea. However, I have yet to see such a screw on any laptop
> power supply that I've torn apart. There usually isn't any room for
> the required plastic pylon inside. There is also some safety rule
> (double insulated???) that requires that the unit NOT create a shock
> hazard by allowing the user to open the case. That's why they glue
> the case shut, and not just snap or screw it together.
>
> >Refining point 1 , place in vice with the weakest point in the line ,
where
> >one of the cables exits.
>
> I beg to differ. The ends are usually not very strong or well
> secured. Compressing the plastic case at the ends is likely to break
> the plastic, and still leave the long glue joints along the sides
> intact. Best to break the long side joints first, and the ends will
> just fall apart.
>
> >A guitar plectrum is best to start with as a pry-bar as minimum damage,
> >progress to screwdrivers etc later.
>
> Yes, that should work. However, at $3/ea, I'm not thrilled.
>
> I think the favored tool is a "spudger" from telco tools and the
> favored tool for prying apart Apple products. Whatever works that
> won't shred the insulation and shielding inside. Avoid anything with
> sharp edges, such as a screwdriver.
>
>
>
>
> --
> 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

Just this last Saturday a Boss PSC 2306 9V, 1A smps "wall wart" psu.
Under the label, a recessed 3mm a/f screw. After that squashed across
cable-weakened short side end in a vice , then other short end, then long
sides and plectrum.

== 2 of 5 ==
Date: Mon, May 30 2011 7:05 am
From: "Ian Field"

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:irufpg$mm6$1@dont-email.me...
> As someone else suggested, an intermittent power supply is almost always
> caused by a defective cable. Regardless, now that it's open, you can touch
> up all the solder joints, and put an ohmeter on the power cord.

A trick I often use on suspect leads is to use a SLA battery and a H4 bulb
with one or both filaments, often an intermittent lead fails to show up on
an ohmeter or continuity tester, the over 4A (or 8A) will make most
intermittent breaks permanent.

Needless to say the OP would be well advised to unsolder the lead from the
PCB before applying this proceedure.

== 3 of 5 ==
Date: Mon, May 30 2011 7:08 am
From: "Ian Field"

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:cfu5u6p8c4ihqo24eqbeggnhvqq0kgsa48@4ax.com...
> On Sun, 29 May 2011 20:21:40 +0100, "N_Cook" <diverse@tcp.co.uk>
> wrote:
>
>>First is to remove any sticky labels that may cover a securing screw.
>
> Good idea. However, I have yet to see such a screw on any laptop
> power supply that I've torn apart. There usually isn't any room for
> the required plastic pylon inside. There is also some safety rule
> (double insulated???) that requires that the unit NOT create a shock
> hazard by allowing the user to open the case.

They often pour potting resin in the screw recess to hide the screw head and
make it nigh impossible to get at.

== 4 of 5 ==
Date: Mon, May 30 2011 7:35 am
From: Robert Macy

On May 29, 7:12 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Sun, 29 May 2011 13:30:46 -0700 (PDT), Robert Macy
>
> <m...@california.com> wrote:
> >The unit used to fail with the LED simply
> >going OFF. If ON, unit was ok.  Could be a lot between the AC mains
> >and that LED, though.
>
> The LED is across the output.  If the cable or connector is shorted,
> then the light will go out.  Look for a short at the plug end of the
> cable or loose shield wires on the output cable.
>
> --
> Jeff Liebermann     je...@cruzio.com
> 150 Felker St #D    http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann     AE6KS    831-336-2558

The case did NOT seem glued, simply very strong plastic detent
fingers.

Changed out the AC cord, made NO difference. Same symptoms. Used the
bottom half of the case simply to hold the assembly and reduce shock
potential - seems unlikely with the shield attached to the PC
connector shield. Then pressed around on the top and found that
pressing near the LED [away from the AC mains port and closer to the
PC port] would cause the LED to momentarily come on, but not stay on.
Have no idea what's flexing to cause this. But need to remove the
fish paper/shield assembly to get good access.

Have to say that this packaging is a marvel to behold. It looks like
the parts were poured into the volume, completely filling it up.

The fish paper, between the copper shield and the PCB seemed to be
glued with a simple 'tacky' type glue and separated easily with the
same 'knife' edge tool, without damaging/distorting its shape.

more later

== 5 of 5 ==
Date: Mon, May 30 2011 10:22 am
From: Robert Macy

On May 29, 10:47 am, Robert Macy <m...@california.com> wrote:
> Have a Battery Technology, Inc. AC Adapter for an IBM Laptop
> IB-PS365, 55W 16V 3.4A
>
> The thing has gone intermittent.  By slightly flexing the case, comes
> back on, so idea is to disassemble, solder traces and be up and
> running instantly.
>
> but...how to disassemble?
>
> Anybody done that?

Found it! Cold solder joint in the middle of the PCB to a large gauge
through hole component. Don't know to what on the other side, but the
wire looked 20 - 22 Awg size and had a neat fuzzy line around it to
the cone of solder, which 'looked' good. Evidently over time the gap
widened until intermittent and then open.

Culmination:
Case SNAPS apart.
Fish paper/copper shield easily opened.
Cold solder joint in the middle of the PCB.

All back together now and working!

Thank you everyone for suggestions.

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

== 1 of 3 ==
Date: Mon, May 30 2011 8:43 am
From: "Vale"

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

== 2 of 3 ==
Date: Mon, May 30 2011 9:27 am
From: "N_Cook"

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

== 3 of 3 ==
Date: Mon, May 30 2011 10:54 am
From: Smitty Two

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?

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

== 1 of 10 ==
Date: Mon, May 30 2011 11:26 am
From: dplatt@radagast.org (Dave Platt)

In article <e3m4u6pu8i5cdkdb8m8jb228u2ghh4ortl@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:
>
>Amazing. I've run tests on some 2200 ma-hr NiMH AA cells using my
>CBA-II
><http://www.westmountainradio.com/product_info.php?products_id=cba3>
>The results are not very impressive. If I discharge at rediculously
>low rates, such as 0.01C, I might be able to squeeze 2200 ma-hr out of
>a cell. I tested one at about twice the estimated self discharge
>rate, and calculated about 5000 ma-hr out of the cell. I think it
>took about a week to finish the test. However, when I ran it at a
>more realistic load of 2C, I was barely able to squeeze out 1000
>ma-hr.

Most NiMH/NiCd battery manufacturers seem to rate their cells at a
discharge rate of 0.05C (20 hour rate) - that would be around 100 mA
for those AA cells. Sanyo's charts for their "Eneloop" show
about a 10% reduction in useful capacity at a discharge rate of 0.5C
(1000 mA).

If you're actually pulling over 4 amps from them (2C discharge rate)
I'd expect a significant further loss of capacity.

For comparison, the same Sanyo charts seem to show that an alkaline
battery loses about 75% of its useful capacity when you go from 100 mA
rates to 1000 mA rates.

I gather that the loss of useful capacity is due in part to the series
resistance of the battery, and in part due to inefficiencies in the
chemistry under high rates of discharge.

> This was also for a brand new cell, as repeated
>charge/discharge cycles would also decrease the cell capacity.

Had these cells been "formed" properly prior to your test (via several
slow-charge / slow-discharge cycles)? There seems to be a general
agreement that NiMH cells don't achieve their maximum storage capacity
unless they've gone through several cycles like this, and that many
manufacturers don't take the time to do this during the manufacturing
process. I've seen some indication of this in my own testing (using a
smart-charger which can cycle the batteries and report the capacities
for each cycle).

--
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 10 ==
Date: Mon, May 30 2011 11:35 am
From: dplatt@radagast.org (Dave Platt)

>Argh. I haven't been paying attention.
> Duracell 2650 2650 ma-hr
> Energizer e2 2500 ma-hr
> Maha Powerex AA 2700 ma-hr
>Maybe I'll do some shopping and testing (timer permitting).

There seems to be a real tradeoff. In general, the very-high-
capacity NiMH cells seem to have a more rapid rate of self-discharge;
they're good for "use immediately after charge" applications, but not
so good for "charge and store" standby uses.

The low-self-discharge cells (e.g. Sanyo Eneloop, PowerEx Imedion, and
similar) seem to run around 10% lower in rated capacity.

For comparison, the Maha Powerex AA are rated at 2700 mAh, while the
Maha Powerex "Imedion" AA are rated at 2400 mAh.

I've read that this is due to difference the structure/alloy of the
metal hydride used for the electrodes... varities which can bind more
hydrogen, also tend to suffer from more spontaneous de-binding and
leakage (or so my crude understanding goes... I probably have the
details wrong).

I've had reasonably good results with the Imedion and Eleloop types
for my radio go-kit... I can charge them up after use, and depend on
finding plenty of power available even six months later. Never could
do that with standard NiMH types, when I tried a few years ago... I
couldn't trust them to be useful even 3 months after charging.

--
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!

== 3 of 10 ==
Date: Mon, May 30 2011 11:37 am
From: "William Sommerwerck"

"Dave Platt" <dplatt@radagast.org> wrote in message
news:u24db8-8sg.ln1@radagast.org...

> Had these cells been "formed" properly prior to your test (via several
> slow-charge / slow-discharge cycles)? There seems to be a general
> agreement that NiMH cells don't achieve their maximum storage capacity
> unless they've gone through several cycles like this, and that many
> manufacturers don't take the time to do this during the manufacturing
> process.

Why should they, when it would add to the cells' cost? Given the relatively
low price of uP-controlleed chargers, there's no point.

== 4 of 10 ==
Date: Mon, May 30 2011 12:02 pm
From: "William Sommerwerck"

"Dave Platt" <dplatt@radagast.org> wrote in message
news:1l4db8-8sg.ln1@radagast.org...

> There seems to be a real tradeoff. In general, the very-high-
> capacity NiMH cells seem to have a more rapid rate of self-discharge;
> they're good for "use immediately after charge" applications, but not
> so good for "charge and store" standby uses.

That hasn't been my experience. My 2200mAh and 2700mAh MAHAs hold up very
well -- months, in fact. I've never made a study of the actual capacity, but
they /do not/ "fall flat" shortly after being put into use.

== 5 of 10 ==
Date: Mon, May 30 2011 12:38 pm
From: Jeff Liebermann

On Mon, 30 May 2011 11:26:06 -0700, dplatt@radagast.org (Dave Platt)
wrote:

>> This was also for a brand new cell, as repeated
>>charge/discharge cycles would also decrease the cell capacity.
>
>Had these cells been "formed" properly prior to your test (via several
>slow-charge / slow-discharge cycles)?

Nope. They came directly out of the box. I didn't record how long
they had been sitting on the shelf. I must admit my ritual was rather
sloppy.

I would initially charge the battery in a Radio Shock 23-1305 charger.
<http://www.buzzillions.com/reviews/radio-shack-30-minute-battery-charger-4-aa-aaa-batteries-reviews>
Not the best, but I have 3 of them, so they get used. One big
advantage for me is that it will independently charge a single AA
cell. Also, it runs off 12VDC. It came with 4ea NiMH cells, but I
killed them long ago.

After charging, I would leave the battery sit for anywhere between 1
and 8 hrs to let it cool down and supply sufficient time to charge up
more cells. I vaguely recall that they were Sanyo cells, but as I
have several types on the bench, I can't tell which one was used.

I would then connect the battery to the CBA-II tester, plug in the
desired test settings, and generate a graph. Repeat for several
cells. I would usually try to discharge it until the "knee" is
visible, which my guess(tm) is down to about 15% of capacity.

I haven't done much NiMH testing (mostly because Li-Ion is my current
interest), but I do recall seeing a drop in capacity with every cycle.
There was no evidence of any "conditioning" effects. Incidentally,
until I see numerical or personal evidence of such a "conditioning"
requirement for NiMH batteries, I prefer to ignore it. To me, it's
the same as NiCd "memory effect", which I have yet to experience, and
which I have spent considerable time attempting to demonstrate.
<http://en.wikipedia.org/wiki/Memory_effect>

>There seems to be a general
>agreement that NiMH cells don't achieve their maximum storage capacity
>unless they've gone through several cycles like this,

I'll believe it when I see it demonstrated, documented, or chemically
explained. I just wasted some time searching Google Scholar for any
references to NiMH conditioning, training, pre-charging, etc. Zilch.

>and that many
>manufacturers don't take the time to do this during the manufacturing
>process. I've seen some indication of this in my own testing (using a
>smart-charger which can cycle the batteries and report the capacities
>for each cycle).

I was watching some TV show (How it's made???) showing how batteries
are manufactured. "Testing" the batteries was done on a high speed
conveyor and lasted about 1/2 second per cell. I don't think this is
enough time to "condition" the battery.

As far as I have been able to guess (Yeah, I know, I should have
measured), the typical NiMH cell arrives out of the box at about 30%
charge. I don't know if this is intentional, an artifact of the
manufacturing process, or some safety requirement. There are quite a
few battery vendors proclaiming that they ship NiMH and other
batteries discharged for safety reasons. Anyway, if they ship them
discharged, then the "conditioning" cycle would need to be:
Full -> discharge -> Full again -> test -> discharge
I wouldn't expect such an exercise for consumer products.

--
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

== 6 of 10 ==
Date: Mon, May 30 2011 1:02 pm
From: Jeff Liebermann

On Mon, 30 May 2011 11:35:45 -0700, dplatt@radagast.org (Dave Platt)
wrote:

>>Argh. I haven't been paying attention.
>> Duracell 2650 2650 ma-hr
>> Energizer e2 2500 ma-hr
>> Maha Powerex AA 2700 ma-hr
>>Maybe I'll do some shopping and testing (timer permitting).
>
>There seems to be a real tradeoff. In general, the very-high-
>capacity NiMH cells seem to have a more rapid rate of self-discharge;
>they're good for "use immediately after charge" applications, but not
>so good for "charge and store" standby uses.
>
>The low-self-discharge cells (e.g. Sanyo Eneloop, PowerEx Imedion, and
>similar) seem to run around 10% lower in rated capacity.

Sanyo Eneloop.
<http://www.eneloop.info/home/performance-details/capacity.html>
<http://www.costco.com/Browse/Product.aspx?Prodid=11504514>
<http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>
<http://www.rcgroups.com/forums/showthread.php?t=630534>

LSD doesn't have lower capacity. It's roughly the same as other NiMH.
LSD NiMH batteries have a higher terminal voltage. The energy
capacity is the area under the discharge curve, which is close to
identical for types with the same chemistry. However, the higher
terminal voltage will cause the curve to drop earlier for the LSD
NiMH, so they appear to not last as long.

Lots of vendors of LSD batteries:
<http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery>

>I've read that this is due to difference the structure/alloy of the
>metal hydride used for the electrodes... varities which can bind more
>hydrogen, also tend to suffer from more spontaneous de-binding and
>leakage (or so my crude understanding goes... I probably have the
>details wrong).

Dunno. I've read some on battery chemistry, but have generally
ignored NiMH as a marginal idea. Sorry(tm).

>I've had reasonably good results with the Imedion and Eleloop types
>for my radio go-kit... I can charge them up after use, and depend on
>finding plenty of power available even six months later. Never could
>do that with standard NiMH types, when I tried a few years ago... I
>couldn't trust them to be useful even 3 months after charging.

Are you running an electric airplane, using the battery pack to run a
glow plug, igniting a squib, or running telemetry electronics? All
would benefit from a switch to Li-Ion.

--
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

== 7 of 10 ==
Date: Mon, May 30 2011 1:21 pm
From: Jeff Liebermann

On Mon, 30 May 2011 12:02:45 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

>"Dave Platt" <dplatt@radagast.org> wrote in message
>news:1l4db8-8sg.ln1@radagast.org...
>
>> There seems to be a real tradeoff. In general, the very-high-
>> capacity NiMH cells seem to have a more rapid rate of self-discharge;
>> they're good for "use immediately after charge" applications, but not
>> so good for "charge and store" standby uses.
>
>That hasn't been my experience. My 2200mAh and 2700mAh MAHAs hold up very
>well -- months, in fact. I've never made a study of the actual capacity, but
>they /do not/ "fall flat" shortly after being put into use.

The reason I bought a CBA-II battery tester was because of my
inability to properly guess actual battery capacity.

Most of my experience with NiMH batteries was with Metricom radios and
various Motorola and Kenwood handheld radios. It doesn't take much to
kill them. For example, you don't even need to discharge them to a
NiMH battery pack. The country distributed Motorola MTS2000 radios to
all the hospitals as part of the HEARNET (Hospital Emergency
Administrative Radio Network) system. The radios were permanently
planted in charger with power on 24x7. Some radios were turned on,
but most were left off. There would be a short test roughly twice per
month. After about a years, not one of the radios were functional
because all the NiMH batteries were dead.

I'm having a similar experience in my palatial office, where I use a
Motorola HT600 and several NTN7016A NiMH battery packs. Unlike the
hospital example, I make it a point of not leaving the battery in the
charger after it reaches full charge. I also use the radio in a
normal manner, charging the battery only when the xmitter craps out.
The result is that I charge the battery approximately 3 times per
week. Despite this care, I manage to kill about one battery every 2
years (that's after only about 150 charge cycles).

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.

--
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

== 8 of 10 ==
Date: Mon, May 30 2011 3:14 pm
From: "William Sommerwerck"

"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).

== 9 of 10 ==
Date: Mon, May 30 2011 3:21 pm
From: dplatt@radagast.org (Dave Platt)

In article <9is7u6pk6r7l5c1meqlcftvnua85klo6rs@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

>Sanyo Eneloop.
><http://www.eneloop.info/home/performance-details/capacity.html>
><http://www.costco.com/Browse/Product.aspx?Prodid=11504514>
><http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf>
><http://www.rcgroups.com/forums/showthread.php?t=630534>
>
>LSD doesn't have lower capacity. It's roughly the same as other NiMH.

Interesting... one of Sanyo's pages shows different results. See

http://www.eneloop.info/home/performance-details/capacity.html

They compare alkaline, Sanyo Eneloop, and the Sanyo "high capacity"
NiMH cells. The latter have a definite advantage in capacity, and the
terminal voltages under load look almost identical in the "100 mA
discharge" graph.

>LSD NiMH batteries have a higher terminal voltage. The energy
>capacity is the area under the discharge curve, which is close to
>identical for types with the same chemistry. However, the higher
>terminal voltage will cause the curve to drop earlier for the LSD
>NiMH, so they appear to not last as long.

Hmmm... the graphs on the page cited above seem to suggest
differently... what do you think?

>Are you running an electric airplane, using the battery pack to run a
>glow plug, igniting a squib, or running telemetry electronics? All
>would benefit from a switch to Li-Ion.

Nope... typical ham-radio handheld radio use (about 80% receive, 20%
transmit).

I do have several such radios which run on LiIon batteries. My
preferred "field assignment" radio is still a NiCd/NiMH type... with
the auxiliary six-AA-cell battery pack, and a bunch of charged
Imedions and some alkaline AA cells as last-ditch backup, I could be
deployed for a couple of days before I'd be in immediate need of a
recharge.

--
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!

== 10 of 10 ==
Date: Mon, May 30 2011 3:47 pm
From: Jim Yanik

Jeff Liebermann <jeffl@cruzio.com> wrote in
news:a4u7u69f03pb04a2o3j3jjbdh9msv9r4ih@4ax.com:

> On Mon, 30 May 2011 12:02:45 -0700, "William Sommerwerck"
><grizzledgeezer@comcast.net> wrote:
>
>>"Dave Platt" <dplatt@radagast.org> wrote in message
>>news:1l4db8-8sg.ln1@radagast.org...
>>
>>> There seems to be a real tradeoff. In general, the very-high-
>>> capacity NiMH cells seem to have a more rapid rate of
>>> self-discharge; they're good for "use immediately after charge"
>>> applications, but not so good for "charge and store" standby uses.
>>
>>That hasn't been my experience. My 2200mAh and 2700mAh MAHAs hold up
>>very well -- months, in fact. I've never made a study of the actual
>>capacity, but they /do not/ "fall flat" shortly after being put into
>>use.
>
> The reason I bought a CBA-II battery tester was because of my
> inability to properly guess actual battery capacity.
>
> Most of my experience with NiMH batteries was with Metricom radios and
> various Motorola and Kenwood handheld radios. It doesn't take much to
> kill them. For example, you don't even need to discharge them to a
> NiMH battery pack. The country distributed Motorola MTS2000 radios to
> all the hospitals as part of the HEARNET (Hospital Emergency
> Administrative Radio Network) system. The radios were permanently
> planted in charger with power on 24x7. Some radios were turned on,
> but most were left off. There would be a short test roughly twice per
> month. After about a years, not one of the radios were functional
> because all the NiMH batteries were dead.
>
> I'm having a similar experience in my palatial office, where I use a
> Motorola HT600 and several NTN7016A NiMH battery packs. Unlike the
> hospital example, I make it a point of not leaving the battery in the
> charger after it reaches full charge. I also use the radio in a
> normal manner, charging the battery only when the xmitter craps out.
> The result is that I charge the battery approximately 3 times per
> week. Despite this care, I manage to kill about one battery every 2
> years (that's after only about 150 charge cycles).
>
> 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.
>

The Everready 2350 mAH cells I've been using for my bicycle LED headlight(2
watts draw,homemade) have been very good in regards to low self-
discharge,much better than I was led to expect.
I also have some "pre-charged" Ray-O-Vac NiMH marked at 2100 mAH that are
advertised as holding their charge much longer.

--
Jim Yanik
jyanik
at
localnet
dot com

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

== 1 of 1 ==
Date: Mon, May 30 2011 12:32 pm
From: tin6150

On May 29, 6:28 pm, whit3rd <whit...@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.

Thanks for everyones reply!
Bugs inside the microwave seems unthinkable but is probably the
problem. Are they trying to eat the HV wiring or something? :)
I will try to disassemble the microwave and see if I can air spray out
any foreign material, but I am not trained to deal with all that high
voltage stuff and so would stay away from it...

Much thanks again.
Tin

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== 1 of 1 ==
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