sci.electronics.repair@googlegroups.com

Today's topics:

* zebra connector - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/22ac512ae9f1d16c?hl=en
* Fuse: fast blown vs slow blown - 7 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/075c97d6b6b6e1f0?hl=en
* Lost in VIDEO signal - 7 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/9ac11c52da1a87d4?hl=en
* NiMH new battery conditioning - 7 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/642feb09361f607e?hl=en
* Video distortion on TV tube - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/54b6737faa12803b?hl=en
* Is there a fuse on a Samsung SV4000? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/d375f8c622c671d0?hl=en
* Stupid question - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/f7521ebc46223e72?hl=en

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

== 1 of 1 ==
Date: Wed, Jun 1 2011 12:34 am
From: "Vale"

"Shaun" <spam@nomail.com> ha scritto nel messaggio
news:oagFp.19079$pi2.11588@newsfe11.iad...
>
>
> "Vale" wrote in message
> news:jK8Fp.29619$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.
>
> 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.
>
It's a Chauvin Arnoux. It is a good idea investigate on spares/kits.I'll do
it, thanks.

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

== 1 of 7 ==
Date: Wed, Jun 1 2011 3:00 am
From: Man-wai Chang

> ** Hey - rice muncher.

Hello, wheat muncher!

> I am in Sydney, Australia.
> BS1362 fuses are used in professional dimmers imported from the UK.

How do you tell they were really BS1362 without any printing on the
fuse? So its look is unique among all fuses?

--
@~@ 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
^ ^ 17:59:01 up 7 days 3:01 0 users load average: 0.97 1.03 1.04
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 7 ==
Date: Wed, Jun 1 2011 3:41 am
From: "Phil Allison"

"Man-wai Chang"
>
>> ** Hey - rice muncher.
>
>> I am in Sydney, Australia.
>> BS1362 fuses are used in professional dimmers imported from the UK.
>
> How do you tell they were really BS1362 without any printing on the fuse?

** Learn to fucking read - you stinking Chink moron.

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

They look much like this - fuckwit.

http://www.betterfuse.com/MyUploadFiles/image/2010-03/2010033110104827.jpg

Figured out what " The quick brown fox jumps over the lazy dog " means
??

Very deep.

.... Phil

== 3 of 7 ==
Date: Wed, Jun 1 2011 4:21 am
From: Jasen Betts

On 2011-05-31, Man-wai Chang <toylet.toylet@gmail.com> wrote:
>
> How dangerous is it to replace a 500mA fast-brown fuse with a 500mA
> slow-brown one?

could be as dangerous as using a nail instead,

--
⚂⚃ 100% natural

== 4 of 7 ==
Date: Wed, Jun 1 2011 5:12 am
From: Man-wai Chang

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

Sorry!

--
@~@ 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
^ ^ 20:09:01 up 7 days 5:11 0 users load average: 1.04 1.09 1.08
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

== 5 of 7 ==
Date: Wed, Jun 1 2011 10:23 am
From: bud--

On Jun 1, 12:09 am, "Phil Allison" <phi...@tpg.com.au> wrote:
> "Winston"
>
>
>
> > Phil Allison wrote:
>
> >>> I didn't know that.
>
> >> ** Cos you know fuck all about anything.
>
> > It's a continuing problem.
> > Watta ya gonna do.  :)
>
> >>> How about this one?
> >>>http://www.flukeonlinestore.com/3478747.html
>
> >> ** Standard glass (fast) fuse by the look of it.
>
> > It must be ~36 times safer than a commodity GMA
> > fuse in a multimeter application, yes?
> >http://www.amazon.com/125mA-250v-Fuses-0-125A-5x20mm/dp/B004HLZYVI
>
> > Fluke wouldn't overcharge for that part either,
> > surely.
>
> ** The price is very steep.
>
> But I expect the fuse IS safe when used in the Fluke DMMs it is specified
> for.
>
> The scenario with a 0.125A fuse is nothing like the one with the 10A range
> fuse.
>
> Typical 0.125A rated fast fuses have resistances of 8 to 10 ohms  -  which
> limits the fault current to a value the fuse can easily break.
>
> A 10 amp fuse may well have a resistance of only a few milliohms, so the
> fault current is only limited by the resistance of the DMM's leads.
>
> A current of 40 amps is easy enough for a small fuse to break, while one of
> over 4000 amps is not.
>
> Capice?
>

Nice post a couple levels up.

Meters like the Flukes are "Category" rated - 1, 2, 3. When working on
high capacity services, like 1000A 480V, you really want a cat 1
meter. You won't wind up wearing it as in your previous post. The
problem is not just the meter. Arc in meter causes vaporized meter
leads that turns into an arc between busbars - very dangerous.

In addition to the nominal voltage you have the hazard of transients
that could start an arc which will then sustain at the nominal
voltage. In the US, OSHA may also take strong exception to using a
meter without the right cat rating.

One of the hazards in high capacity services is available fault
current, which can be 200,000A. Fuses have a rating for available
fault current. The fix is to use "current limiting" fuses. For high
currents they have a clearing time of under 1/4 cycle. You handle a
200,000A available location by the fuse clearing before the current
increases to anything near that value. The earlier Fluke fuse is
certainly current limiting. The fuse opens before the meter leads turn
to plasma.

The fuse in the later link is a mere 250V - not likely a cat 1 meter.
But a glass 250V GMA fuse in a meter may exceed the fault current
rating for the fuse. One of the fuses in my Fluke is 0.44A and is
almost certainly current limiting.

--
bud--

== 6 of 7 ==
Date: Wed, Jun 1 2011 11:30 am
From: Winston

bud-- wrote:

(...)

> Nice post a couple levels up.

Thanks!

> Meters like the Flukes are "Category" rated - 1, 2, 3. When working on
> high capacity services, like 1000A 480V, you really want a cat 1
> meter. You won't wind up wearing it as in your previous post. The
> problem is not just the meter. Arc in meter causes vaporized meter
> leads that turns into an arc between busbars - very dangerous.

I learned about 'flashover' only very recently.
Once you know about it, it's obvious.

> In addition to the nominal voltage you have the hazard of transients
> that could start an arc which will then sustain at the nominal
> voltage. In the US, OSHA may also take strong exception to using a
> meter without the right cat rating.
>
> One of the hazards in high capacity services is available fault
> current, which can be 200,000A. Fuses have a rating for available
> fault current. The fix is to use "current limiting" fuses. For high
> currents they have a clearing time of under 1/4 cycle. You handle a
> 200,000A available location by the fuse clearing before the current
> increases to anything near that value. The earlier Fluke fuse is
> certainly current limiting. The fuse opens before the meter leads turn
> to plasma.

So *that's* the '40,000 A' number in the 11A fuse ratings.
I always wondered about those stunningly huge numbers.

> The fuse in the later link is a mere 250V - not likely a cat 1 meter.

I pointed to that fuse to show that Fluke were not
undercharging for replacement parts. :)
That fuse is in a 'hobby / light industrial' instrument.

> But a glass 250V GMA fuse in a meter may exceed the fault current
> rating for the fuse. One of the fuses in my Fluke is 0.44A and is
> almost certainly current limiting.

That's the same package as the 11 A fuse I originally mentioned.

Ironically, I popped it measuring automotive electrical stuff.
(Note to self: Don't leave meters on the bench with the probes
connected to measure current!) :)

Lesson learned.

--Winston

== 7 of 7 ==
Date: Wed, Jun 1 2011 11:32 am
From: Winston

Phil Allison wrote:

(...)

> Piss off wanker.

You are so beautiful when you are angry, Phil.

--Winston :)

==============================================================================
TOPIC: Lost in VIDEO signal
http://groups.google.com/group/sci.electronics.repair/t/9ac11c52da1a87d4?hl=en
==============================================================================

== 1 of 7 ==
Date: Wed, Jun 1 2011 6:15 am
From: benitos

Hi ,

We have a CCTV cam (Bosh WZ18) that is 1500 feet from the LCD display.

The cable that was used is a RG59 and having 2 splices (2 junctions).

The video signal is poor , we can see tha image but with lines and
it's noisy.

Is there a way to improve or "rebuild" the signal ?

I tried a VID-AMP SPECO / PROVIDEO VID-AMP 1 IN / 1 OUT VIDEO
AMPLIFIER but did not help.

http://www.surveillance-video.com/vid-amp.html

== 2 of 7 ==
Date: Wed, Jun 1 2011 6:29 am
From: "Dave M"

benitos wrote:
> Hi ,
>
> We have a CCTV cam (Bosh WZ18) that is 1500 feet from the LCD display.
>
> The cable that was used is a RG59 and having 2 splices (2 junctions).
>
> The video signal is poor , we can see tha image but with lines and
> it's noisy.
>
> Is there a way to improve or "rebuild" the signal ?
>
> I tried a VID-AMP SPECO / PROVIDEO VID-AMP 1 IN / 1 OUT VIDEO
> AMPLIFIER but did not help.
>
> http://www.surveillance-video.com/vid-amp.html

A few questions to maybe lead you to the problem...
Do you have a good picture when the display is connected close to the
camera? If not, then either the camera or the display is bad. If yes, then
the coax or the splices might be bad. Does the picture degrade when the amp
is connected?
Where do you have the video amp installed? It should be close to the
camera; not the display.
Are the camera and amp getting good power?
Are the spliced connections clean and dry?
Is the coax in good shape? Is it old?
--
David
dgminala at mediacombb dot net

== 3 of 7 ==
Date: Wed, Jun 1 2011 7:20 am
From: benitos

On Jun 1, 9:29 am, "Dave M" <dgminala4...@mediacombb.net> wrote:
> benitos wrote:
> > Hi ,
>
> > We have a CCTV cam (Bosh WZ18) that is 1500 feet from the LCD display.
>
> > The cable that was used is a RG59 and having 2 splices (2 junctions).
>
> > The video signal is poor , we can see tha image but with lines and
> > it's noisy.
>
> > Is there a way to improve or "rebuild" the signal ?
>
> > I tried a VID-AMP SPECO / PROVIDEO VID-AMP 1 IN / 1 OUT VIDEO
> > AMPLIFIER but did not help.
>
> >http://www.surveillance-video.com/vid-amp.html
>
> A few questions to maybe lead you to the problem...
> Do you have a good picture when the display is connected close to the
> camera?  If not, then either the camera or the display is bad.  If yes, then
> the coax or the splices might be bad.  Does the picture degrade when the amp
> is connected?
> Where do you have the video amp installed?  It should be close to the
> camera; not the display.
> Are the camera and amp getting good power?
> Are the spliced connections clean and dry?
> Is the coax in good shape?  Is it old?
> --
> David
> dgminala at mediacombb dot net- Hide quoted text -
>
> - Show quoted text -

Hi , it's a brand new cable. Splices are good. Signal at the CAM is
good. I cannot connect the AMP to the CAM side , only at the Display
side. That's an issue.

I thing the problem here is the lenght of the cable. Usually , RG6
would be better and less than 1000 feet. 1500 feet is very long.

Thanks

== 4 of 7 ==
Date: Wed, Jun 1 2011 7:38 am
From: "Phil Allison"

"benitos"

I cannot connect the AMP to the CAM side , only at the Display
side. That's an issue.

** How are you getting power to the camera ?

( runs on 12V DC or 24VAC at about 4 watts )

... Phil

== 5 of 7 ==
Date: Wed, Jun 1 2011 8:55 am
From: benitos

On Jun 1, 10:38 am, "Phil Allison" <phi...@tpg.com.au> wrote:
> "benitos"
>
> I cannot connect the AMP to the CAM side , only at the Display
> side. That's an issue.
>
> ** How are you getting power to the camera  ?
>
>   ( runs on 12V DC or 24VAC at about 4 watts )
>
> ...  Phil

I put 24VAC to the CAM now.

On DC12 , cable is too long ,was getting 6.5 volts to the CAM.

== 6 of 7 ==
Date: Wed, Jun 1 2011 9:11 am
From: Jeff Liebermann

On Wed, 1 Jun 2011 06:15:01 -0700 (PDT), benitos <pothier@cae.ca>
wrote:

>We have a CCTV cam (Bosh WZ18) that is 1500 feet from the LCD display.

Much too long a cable.

>The cable that was used is a RG59 and having 2 splices (2 junctions).
>
>The video signal is poor , we can see tha image but with lines and
>it's noisy.
>
>Is there a way to improve or "rebuild" the signal ?
>
>I tried a VID-AMP SPECO / PROVIDEO VID-AMP 1 IN / 1 OUT VIDEO
>AMPLIFIER but did not help.
>
>http://www.surveillance-video.com/vid-amp.html

Intersil makes a line of video equalizer chips that will correct the
video signal for frequency dependent line losses:
<http://www.intersil.com/video/>
There are different chips for different for different lengths.
<http://www.intersil.com/products/deviceinfo.asp?pn=ISL59601>
<http://www.intersil.com/products/deviceinfo.asp?pn=ISL59602>
<http://www.intersil.com/products/deviceinfo.asp?pn=ISL59603>
The problem is that these chips were not really intended to operate as
an external line driver/receiver pair, but rather to be designed into
the camera. There may be such coax cable video equalizer
driver/receiver pairs, but I couldn't find any. All I can find are
video coax extender kits, such as:
<http://cgi.ebay.com/250802822707>

--
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 7 ==
Date: Wed, Jun 1 2011 9:13 am
From: Jeff Liebermann

On Wed, 01 Jun 2011 09:11:57 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>Intersil makes a line of video equalizer chips that will correct the
>video signal for frequency dependent line losses:
><http://www.intersil.com/video/>
>There are different chips for different for different lengths.
><http://www.intersil.com/products/deviceinfo.asp?pn=ISL59601>
><http://www.intersil.com/products/deviceinfo.asp?pn=ISL59602>
><http://www.intersil.com/products/deviceinfo.asp?pn=ISL59603>

I forgot the data sheet. Note the photos of the video quality:
<http://www.intersil.com/data/fn/fn6739.pdf>

--
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

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

== 1 of 7 ==
Date: Wed, Jun 1 2011 8:54 am
From: Jeff Liebermann

On Tue, 31 May 2011 11:27:21 -0700, dplatt@radagast.org (Dave Platt)
wrote:

>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.

Like the alleged increase in NiMH capacity produced by initially
"conditioning" the battery, there's the question of how much does
quick charging a battery reduce its overall life? According to
various documents which I'm too lazy to find, a cell is considered
dead when it reaches 50% of its rated capacity. One text mumbled that
quick charging will reduce the number of charge cycles by 20%. For a
400 to 800 charge cycle battery, that would be not a big deal for
cheapo AA cells, and a major cost issue for expensive radio battery
packs.

My guess(tm) is that internal heating is doing the damage. With a
defacto standard 16r 0.1C charge, there's some excess power going into
heat. For a perfect battery, 10 hrs of this 0.1C is all that's
required to get to 100%. The other 6 hrs of charge is going
somewhere, most likely into heat. Over a 16 hr charge, that's not
going to heat up the battery much. Over a 0.25 hr 4C charge, that's
quite a bit of power heating the battery. Note that the internal
resistance (ESR) of the battery also heats the battery on discharge,
making a rapid discharge risky.

So, why the wide variation in capacity and recommended charging
methods? Because none of them will satisfy everyone. If you ask
marketing, they will offer the highest possible science fiction
capacity, over unrealistic discharge times (20 hr), with the fastest
possible (4C) recharge because that's what consumers want. If you ask
the company legal counsel, they will offer a much lower capacity to
avoid getting sued, and the safest possible recharge method, for the
same reason. Everyone lies, but that's ok because nobody listens.

The problem is that I don't have the time to run a proper test. I
could take one of the brand new Energizer cells, charge at 4C (15
min), discharge at 1C (about 45 min), and repeat as many times as it
takes for the battery capacity to drop 50% from 2300 ma-hr. Without
automation, my guess is that I can do about 4 cycles per day. That
will take 3 months before I kill 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.

Sorta. The amount of heat (calories) produced by fast or slow
charging is the same. However, with fast charge, the heat is produced
over a much shorter period, resulting in a much higher cell
temperature. Methinks it's this temperature that kills the cells.

Incidentally, I learned the hard way with NiCd batteries that once the
heat gets to the case and is able to be measured, it's too late. The
internal damage is already done. Internal sensors are required.

Note the magnetic temperature sensor on my battery fixture (that has
fallen off and landed on the spring).
<http://802.11junk.com/jeffl/NiMH/cba-II.jpg>

>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).

Yep. Quick charging will produce a higher cell temperature which is
easier to detect.

During my experiments with NiCd batteries, I've found that I can
charge a single cell at almost any rate (I've done 20C). As long as
the battery is below 100% capacity, there is almost no heating. As
the battery approaches about 95% of capacity, the heating starts, and
rapidly increases. I've quick charged 650 ma-hr NiCd batteries to
almost full charge in about 3 minutes. However, there's a catch. If
I miss the 95% point, and go over, the overcharge will either kill the
battery, or vent boiling caustic electrolyte. It's for this reason
that I suspect really quick chargers are not sold or recommended. I
have not done any such testing with NiMH.

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

Fishing boats like to run quiet, with the engine off. There are also
sailboats and small boats that only charge the battery at the dock.
(These daze, they have solar chargers). It's not unusual for them to
use crappy batteries, that have a no charge terminal voltage of
10-11VDC. Getting 10 watts output from a 25w bipolar Class-C stage at
10VDC was not easy.

>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.

Note the misuse of the words "peak charge". It should say "peak
capacity". Kinda reads like this was written by marketeering, not
engineering. If they had mentioned that ignoring this sage advice
might result in an initial loss of 10-15% of peak capacity (per my
tests), I suspect that users would probably ignore the problem.
However, because the effect is not innumerated, it looks a major
problem.

So, if I cycle a new NiMH battery with a 4C charge, and a 1C
discharge, how many cycles would you guess I would get before the
battery hits 50% of rated capacity? The winner gets what's left of
the test battery (suitable for recycling) when I'm done.

--
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 7 ==
Date: Wed, Jun 1 2011 9:01 am
From: Jeff Liebermann

On Wed, 01 Jun 2011 08:54:57 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>Sorta. The amount of heat (calories) produced by fast or slow
>charging is the same. However, with fast charge, the heat is produced
>over a much shorter period, resulting in a much higher cell
>temperature. Methinks it's this temperature that kills the cells.

That kinda begs the question if submerging the cell in cooling water
will allow for a fast charge (4C) without overheating and killing the
battery? I can see it now... the super-fast battery charger, just add
coolant.

--
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 7 ==
Date: Wed, Jun 1 2011 9:06 am
From: "William Sommerwerck"

Several years ago I ran tests using name-brand AA alkalines and 2500mAh NiMH
cells to power a STAX headphone amplifier. (This was not completely valid,
because I had no idea what the alkaline cells' rated capacity was. Does
anybody know?)

Much to my surprise, I discovered that the rechargeable cells powered the
unit as long as the throwaways. This means I'd break even after only 10
recharges. Even if I was off by 50%, I'd still need only 20 recharges.

The shortened life of fast recharging has to be weighed against the cost of
using throwaways. In practice -- particularly with heavy-drain devices --
you don't need many charge/recharge cycles to break even.

This is why I carry multiple sets of NiMH cells for my flashes and other
heavy-drain devices. With multiple sets, I don't have to worry about rapid
recharging, and can stick with 0.2C or 0.3C.

== 4 of 7 ==
Date: Wed, Jun 1 2011 9:28 am
From: Jeff Liebermann

On Wed, 1 Jun 2011 09:06:40 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

>Several years ago I ran tests using name-brand AA alkalines and 2500mAh NiMH
>cells to power a STAX headphone amplifier. (This was not completely valid,
>because I had no idea what the alkaline cells' rated capacity was. Does
>anybody know?)

It varies radically with load. With a very light load, it's as high
as 2000 ma-hr. With a heavy 1 amp load, as little as 550 ma-hr.
However, even that's not consistent. I was comparing Costco Kirkland
alkaline AA batteries, with the equivalent Duracell, Ray-o-Vac, etc
cells. The cheapo Kirkland cells were far better with a 1A load, but
sucked with a light load. Duracell was the exact opposite. The
differnces were not huge, but they were reproducable.

More than you ever wanted to know about alkaline batteries:
<http://www.powerstream.com/AA-tests.htm>
Note the variations by brand and type and the NiMH cell in the bottom
graph.

>Much to my surprise, I discovered that the rechargeable cells powered the
>unit as long as the throwaways. This means I'd break even after only 10
>recharges. Even if I was off by 50%, I'd still need only 20 recharges.

Headphone amps sound like a light load. Got a number for the average
current drain?

>The shortened life of fast recharging has to be weighed against the cost of
>using throwaways. In practice -- particularly with heavy-drain devices --
>you don't need many charge/recharge cycles to break even.

I killed a small Canon camera by using alkalines. It was apparently
designed for the normal terminal voltages found with NiCd and NiMH.
When I stuffed in an alkaline cell, the camera overheated after about
30 shots, and died. Canon covered it under the warranty.

Also, NiMH can handle short duration high current loads much better
than alkaline. That's they type of load found in many digital
cameras. Alkaline might be an option for a low current load such as
your headphones, but they wouldn't last long in a high current camera.

>This is why I carry multiple sets of NiMH cells for my flashes and other
>heavy-drain devices. With multiple sets, I don't have to worry about rapid
>recharging, and can stick with 0.2C or 0.3C.

I've had problems with self discharge in previous NiMH batteries. So,
I have a 117VAC/12DC fast (4C / 15 min) charger in the camera bag.
When I need to shoot lots of photos, I give it a quick charge. Maybe
the LSD (low self discharge) NiMH will eliminate this problem.

--
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 7 ==
Date: Wed, Jun 1 2011 9:35 am
From: Jeff Liebermann

On Wed, 01 Jun 2011 08:54:57 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

More on how NiMH charging:
<http://www.powerstream.com/NiMH.htm>

--
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 7 ==
Date: Wed, Jun 1 2011 10:31 am
From: "William Sommerwerck"

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:ddpcu69fvgl4lb0fml8hsultltcmslgehi@4ax.com...
> On Wed, 1 Jun 2011 09:06:40 -0700, "William Sommerwerck"
> <grizzledgeezer@comcast.net> wrote:

>> Much to my surprise, I discovered that the rechargeable cells powered the
>> unit as long as the throwaways. This means I'd break even after only 10
>> recharges. Even if I was off by 50%, I'd still need only 20 recharges.

> Headphone amps sound like a light load. Got a number for the average
> current drain?

The operative word here is STAX -- as in high-voltage electrostatic
earphones. I never measured the drain, but neither set of cells lasted much
more than four hours.

>> This is why I carry multiple sets of NiMH cells for my flashes and other
>> heavy-drain devices. With multiple sets, I don't have to worry about
rapid
>> recharging, and can stick with 0.2C or 0.3C.

> I've had problems with self discharge in previous NiMH batteries. So,
> I have a 117VAC/12DC fast (4C / 15 min) charger in the camera bag.
> When I need to shoot lots of photos, I give it a quick charge. Maybe
> the LSD (low self discharge) NiMH will eliminate this problem.

We still don't have a rational answer as to why some people don't have
problems with rapid self-discharge.

I don't shoot every day, so I can charge-up the night before. I have two
chargers, which makes things easier.

== 7 of 7 ==
Date: Wed, Jun 1 2011 11:50 am
From: Jeff Liebermann

On Wed, 1 Jun 2011 10:31:48 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

>"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
>news:ddpcu69fvgl4lb0fml8hsultltcmslgehi@4ax.com...
>> On Wed, 1 Jun 2011 09:06:40 -0700, "William Sommerwerck"
>> <grizzledgeezer@comcast.net> wrote:
>
>>> Much to my surprise, I discovered that the rechargeable cells powered the
>>> unit as long as the throwaways. This means I'd break even after only 10
>>> recharges. Even if I was off by 50%, I'd still need only 20 recharges.
>
>> Headphone amps sound like a light load. Got a number for the average
>> current drain?
>
>The operative word here is STAX -- as in high-voltage electrostatic
>earphones. I never measured the drain, but neither set of cells lasted much
>more than four hours.

$2,000 for earphones and you're worrying about the price of
rechargeable batteries? Argh.

There seems to be two amps. One with tubes and the other presumably
IC's.
<http://www.stax.co.jp/Export/ExportProducts.html>
55 watts and 46 watts power consumption from an internal 117VAC power
supply. No batteries in sight. Wrong unit?

>We still don't have a rational answer as to why some people don't have
>problems with rapid self-discharge.

Oh, that's easy. How many charge cycles would you guess you get on a
set of NiMH before they're ready to recycle? You probably don't know
and neither does Joe Sixpack. I don't even know because nobody is
counting. So, Joe Sixpack may get 2 years of service out his NiMH
battery pack, but has only charged it perhaps 20 times before it died.
I vaguely know someone that maintains TV camera battery packs for one
of the major networks. Current technology is Li-Ion but in the not so
distant past, it was NiMH and NiCd. He keeps meticulous records. I
must admit that I wasn't paying attention when he showed me the
numbers, but it seemed to me that even for identical battery packs,
the numbers were almost random. Some would last on a few charge
cycles, while other would last seemingly forever. He attributed this
mostly to depth of charge and storage temperature. Even the best
battery, stored hot, will die prematurely. This is a known problem
with Li-Ion, but I'm not sure if storage temperature has any effect on
NiMH. Mine are all in the fridge, just in case. Depth of charge is
the biggie. A battery that is only discharged to perhaps 75% of full
charge, can be charge cycled many more times than one that is fully
discharged before recharging. However, if the charger is too
aggressive, a battery that's discharged to 75% might be overcharged,
while the one that's fully discharged is less likely to be
overcharged.

>I don't shoot every day, so I can charge-up the night before. I have two
>chargers, which makes things easier.

I have 3 fast chargers. House, office, and vehicle. The one in the
vehicle seems to get the most use.

--
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

==============================================================================
TOPIC: Video distortion on TV tube
http://groups.google.com/group/sci.electronics.repair/t/54b6737faa12803b?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jun 1 2011 8:54 am
From: "Dave"

Okay, I've fixed the vertical hold problem mentioned in another string of
posts, and now the bottom of the picture is overlaid or superimposed over
the top of the picture, at the top of the screen,. I was thinking this is
most likely an adjustment, but couldn't find the pot that affected it and
ended up pulling the CRT out to gain access to and adjust a variable
inductor at the back middle of the PC board. So now the problem is not as
bad, but it's still there. I'm guessing this is some sort of wrap-around,
but have no idea as to what to do about it. Any suggestions? Surely this
isn't the first time something like this as happened with a TV. There are
four pots on this board, but one of them doesn't seem to do anything to the
picture, so I am trying to leave it where it was. If anyone has any ideas,
I'm all ears.

Thanks bunches.

Dave

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

== 1 of 1 ==
Date: Wed, Jun 1 2011 10:48 am
From: Geo

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!

It opened fine with Irfanview - and is a 14 page schematic.
Page 8 shows a 2A fuse.

==============================================================================
TOPIC: Stupid question
http://groups.google.com/group/sci.electronics.repair/t/f7521ebc46223e72?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jun 1 2011 11:47 am
From: klem kedidelhopper

Lately I've had more than a few flat screens in the shop with bulged
capacitors in the power supply. I've noticed that in many of these
sets there might be for instance two or three 1000UF caps in parallel.
Is there any reason in the manufacturing process to parallel three
1000UF capacitors when one 3300UF would do the job? Lenny

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