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

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

sci.electronics.repair@googlegroups.com

Today's topics:

==============================================================================
TOPIC: HOLLYWOOD ACTRESS SO HOT VIDEOS AND PICTURES HERE
http://groups.google.com/group/sci.electronics.repair/t/acc78ea8280e5b8f?hl=en
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== 1 of 1 ==
Date: Thurs, Mar 31 2011 7:25 am
From: devi vithya

http://cinemano1maha.blogspot.com/

==============================================================================
TOPIC: Foregoing warranty rights
http://groups.google.com/group/sci.electronics.repair/t/db33289fb500ca5c?hl=en
==============================================================================

== 1 of 4 ==
Date: Thurs, Mar 31 2011 7:30 am
From: "N_Cook"

Anyone else coming across this ? Twice in about 2 months, an owner of new
music kit wanting me to repair intermittant faults after being used only a
few times from new. So loosing his warranty rights. 2 different companies ,
reason for first owner foregoing his rights, unknown. This second time
owner was quoted 2 months minimum turn around, sending back to the factory
(import/asembly plant) in another part of the country, but otherwise no
charge. Is there an excessive number of returns these days or what is the
reason?

== 2 of 4 ==
Date: Thurs, Mar 31 2011 2:51 pm
From: Jeff Liebermann

On Thu, 31 Mar 2011 15:30:03 +0100, "N_Cook" <diverse@tcp.co.uk>
wrote:

>Anyone else coming across this ?

Yes. It's a major source of my business. Usually it's someone who
has purchased an extended warranty with onsite repair, that is on try
#3 to get it fixed right. Some things just can't be done at the
customers home or office. Similarly, with purchases of Apple Care,
who really don't want to wait up to 4 months to get their whatever
fixed. If they really need their computer to working now, they'll
forego the warranty and deal with a disreputable but fast repair
person like me.

>Twice in about 2 months, an owner of new
>music kit wanting me to repair intermittant faults after being used only a
>few times from new. So loosing his warranty rights. 2 different companies ,
>reason for first owner foregoing his rights, unknown. This second time
>owner was quoted 2 months minimum turn around, sending back to the factory
>(import/asembly plant) in another part of the country, but otherwise no
>charge. Is there an excessive number of returns these days or what is the
>reason?

It's the 2 month delay that is probably the primary incentive. A
friend, looking over my shoulder, casually mentioned that it took a
large telescope manufacturer about 7 months to return his telescope
for out of warranty repair. Delays are also not very consistent. I've
seen amazingly fast turn around by HP and Dell on warranty repairs
(usually exchange for another repaired unit), followed by atrocious
delays the next month, sometimes losing the item. My guess is that
all these vendors are using outsourced repair facilities, which are
having their own problems ranging from too much business (overload),
to variations on ineptitude.

Locally, the various authorized service centers, are constantly
complaining about delivery delays on replacement components. Their
contract with the manufacturer requires that they use only brand new
parts, obtained directly from the manufacturer. No eBay or
cannibalized parts. So, the customers waits, even though the missing
part is sitting only a few feet away.

Drivel: You have no idea how many laptop hinges I repair. Actually,
I have no idea either as I don't keep count, but it's plenty. Broken
hinges seem to be a problem. Some vendors cover them under warranty,
while others claim that since their hinges are perfect, it must be
customer abuse that caused them to break apart.

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

== 3 of 4 ==
Date: Thurs, Mar 31 2011 2:56 pm
From: Jeff Liebermann

On Thu, 31 Mar 2011 14:51:36 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:
(...)

I forgot to include my warranty certificate:
<http://802.11junk.com/jeffl/pics/drivel/slides/diploma.html>

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

== 4 of 4 ==
Date: Thurs, Mar 31 2011 3:44 pm
From: "Phil Allison"

"Jeff Liebermann"
>
> I forgot to include my warranty certificate:
> <http://802.11junk.com/jeffl/pics/drivel/slides/diploma.html>

** ROTFL !!

You have inspired me to maybe create something similar.

The audio gear I see and repair is all used in live entertainment, both
portable and installed systems.

At least 90% of the failures are CAUSED by careless an continuous abuse of
the gear - I consider turning all the knobs on a Marshall up to 10 and
thrashing it to death to be in that category.

So, my repair guarantee goes like this:

" I guarantee that if you continue to abuse any item I have repaired for you
OR do again the same stupid thing that caused it to fail before - it is
GUARANTEED to fail again.

The usual service charges apply to all items covered under this guarantee. "

.... Phil

==============================================================================
TOPIC: motherboard RAM failures
http://groups.google.com/group/sci.electronics.repair/t/3e25b3ae78058770?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Mar 31 2011 7:48 am
From: Jeff Liebermann

On Thu, 31 Mar 2011 05:15:41 -0400, JW <none@dev.null> wrote:

>On Wed, 30 Mar 2011 08:50:30 -0700 Jeff Liebermann <jeffl@cruzio.com>
>wrote in Message id: <oui6p6l2pbc53qa6mbghk2q5vfam21qq2u@4ax.com>:
>
>>Corsair "Dominator" RAM series is the favored RAM for overclocking
>>adventures. They even advertise it.
>><http://www.corsair.com/memory/dominator.html>
>>As I recall, when I tore apart one of their DDR2 sticks, it's Intel
>>chips, with a useless aluminum heat sink attached mostly for
>>aesthetics.
>
>Huh? I believe Intel stopped making DRAM back in the 80's.

Y'er right. I recall seeing Intel markings on the chips, but that was
a few months ago, I was in a hurry, etc. I may have been mistaken.
I'll see if I can find a Corsair DDR3 stick and look inside. Randomly
skimming through the Intel validated RAM lists, I couldn't find
Corsair:
<http://www.intel.com/technology/memory/>

Some Googling didn't find any references to the chip vendor(s) for
Corsair RAM. The apparently were using Elpida RAM:
<http://www.zdnet.com/blog/hardware/corsair-pulls-dominator-gt-ddr3-memory-because-of-failures/4886>
but were having problems 2 years ago.
Oh-oh... perhaps old stock DDR3 RAM?

--
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 2 ==
Date: Thurs, Mar 31 2011 10:16 am
From: Meat Plow

On Wed, 30 Mar 2011 16:57:48 -0700, Jeff Liebermann wrote:

> On Wed, 30 Mar 2011 18:56:09 +0000 (UTC), Meat Plow <mhywattt@yahoo.com>
> wrote:
>
>>I've run several raw digital videos back to back encoding them to DVD
>>but even at 10x encode rate I can't get the CPU load up to more than
>>50%. Not even enough load to speed the CPU fan up past 1800 which is
>>still an idle speed.
>
> Nice, but depending upon how you're running that test, the CPU could be
> waiting for HD I/O, which might explain why it's at 50% idle. Try a CPU
> and/or RAM only benchmark to see how your overclocking is doing.

It's not idling at 50%. That's the highest CPU load that I can manage
with the video software. Actually any software I have. My video card
is pre-CUDA support else-wise CPU load would be less than 50%.

>>Don't really need to burn anything in or force a failure artificially. I
>>might do that if there was a problem.
>
> Awwww.... you're no fun.

Yeah I know. No need to heat the soup up unless it's time to eat.

>>> Nice. One of these days, in my non-existent spare time, I'll build
>>> myself a high end machine. Thanks for the pointers.
>
>>$500 got all three items. Probably lots cheaper now Already had an Antec
>>server case. Has a 120mm fan in back and a vent tube the size of the CPU
>>fan with access to the
>>side case so the CPU draws its own fresh air in. The tube covers the top
>>of CPU fan. I thought it was a great idea.
>
> I've seen a few boxes with fans like that. They work quite well for
> cooling the CPU, but seems to require a 2nd fan to cool the rest of the
> system. I've seen video cards that suck almost as much power as the
> CPU. $500 for all that is cheap, even with todays prices.

The side vent has a tube you can adjust over the CPU cooler. And flairs
at the end so it covers the cooler inside. Just wanted to make sure I
stated that correctly. Sometimes my descriptions suck. There is an
aditional PCM controlled 120mm fan mounted under the PSU on the real
panel The PSU has a load controlled 120mm fan.

>>It's a quiet machine also. Rubber mounted hard drives x3. The case has
>>sound dampening on the sides and a locking cover for the drive bay. I
>>can't handle a loud PC.
>
> I have the same problem. I *HATE* noisy machines. About 2 years ago, I
> went on a noise reduction purge and replaced my office and home
> computers with Dell Optiplex 960 and 755 mini-tower machines
> respectively. Both use a single 120mm fan for cooling. No other fans
> in the box. The fan normally rotates quite slowly, which makes it very
> quiet. When I run Bench95 to heat up the CPU, the fan gets quite noisy.

Yeah the Dell desktops both home and office versions always used a
large slow rotating fan with a shroud over the CPU. Made them popular
for being quiet.

> At full speed, it could probably lift the PC off the table.
> No shock mounting on the hard disk drives. If there was enough noise
> and/or vibration to warrant a shock mount, I would also suspect that the
> drive was off balance or ready to blow. Some boxes allow the side to
> act as a sounding board for the drive noises, which I guess justifies
> sound dampening. I've done as well with stiffeners, battens, and
> fiberglass matting on the sides.

The screws for the hard drives go through a silicone grommet. All drives
make some noise and there's space in this case for 4. I have a mini ATX
case that I used with 1 drive prior to building this. You could hear the
drive spin and click. This case with 3 drives you cannot unless you hold
your ear up to the front.

> Incidentally, I once had a PC (PIII/866) that had no fans. It used heat
> pipes, liquid coolant, and a small aquarium pump to move the heat to
> outside of the box. Worked nice until I found anti-freeze all over the
> carpet.
>
> More recently, I spent some time playing with two "no-fan" ATX power
> supplies. This was one
> <http://www.fspgroupusa.com/zen-400/p/412.html> but I don't recall the
> other model. It had a big copper heat sink sticking out the back of the
> machine. I burned myself several times during testing. Both worked,
> but with limitations. The Zen-400 would accumulate heat inside the
> case, between the top of the case and the power supply. No air flow in
> that area would make the top rather hot. The other would probably scorch
> anything that came in contact with the copper heat sink. Meltdown and
> fire is a small price to pay for a quiet PC.

I used to offer a micro pc to clients. It had no fans either. Sold a few
of them but they weren't upgradeable.

My son has a Intel P4 @ 3ghz. Has a large PCM fan on the CPU. Pretty
quiet most of the time unless he's playing a game. The CPU fan ramps
up and down with the load of the game. It will whine when the heatsink
gets clogged with dust. Can definitely tell when it's time to detatch the
fan and brush and vacuum it out. The maker anticipated this and the fan
is latched on, easy to remove to clean. It's been long enough now for
this one to get its first cleaning. I've cleaned the side vent off
several times as dust gathers rather quickly over the inlet. It's not a
screen but a circle of closely drilled small holes.

--
Live Fast Die Young, Leave A Pretty Corpse

==============================================================================
TOPIC: Backwards electrolytics (again)
http://groups.google.com/group/sci.electronics.repair/t/1ce61685a5164a31?hl=en
==============================================================================

== 1 of 7 ==
Date: Thurs, Mar 31 2011 7:56 am
From: Jeff Liebermann

On Thu, 31 Mar 2011 21:36:31 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:

> ** With all those damn electros installed in reverse polarity, be a damn
>site easier to alter the DC rails to suit - wouldn't it ??

I thought you would be amused. I don't think that the IC's would
appreciate the reversed power supply polarity.

It took me about 45 minutes to tear down the XPS-200, replace 11 caps,
reassemble, and test. It's now running an overnight burnin. I also
fixed two of the other machines in about 30 minutes each (fewer caps
to replace). What I found interesting was that the XPS-200 again
worked for about a week with reverse polarized caps. My usual 24
burnin is probably inadequate as I didn't bother doing a visual or
thermal inspection after the burnin.

Yes, I also learn from my mistakes.

--
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: Thurs, Mar 31 2011 8:09 am
From: Jeff Liebermann

On Wed, 30 Mar 2011 21:00:22 -0700 (PDT), stratus46@yahoo.com wrote:

>Good grief man, take some digital pix before you take it apart - at
>least until you get over your brain fades.

Welcome to Learn By Destroying(tm).

I take photos of every customers machine I work on. I blow off the
dust outside (so that it doesn't trash the office), take a few photos,
and then proceed to work on the machine. This has ended a few debates
over missing accessories, mechanical damage, etc. Sometimes, I use
one of the particularly disgusting photos as wallpaper on the repaired
machine. I also take some more photos when I'm done.

However, these were my machines, not customers, so I didn't bother
with the photos. Most were rescued from the recyclers and all of them
had bulging caps. Since these were mine, not customers, all my
customary precautions were ignored. Out of about 7 machines, I
managed to reverse the caps on 4 of them. All had the silk screened
stripe marking the "+" end instead of the usual "-" end. I didn't see
the "+" silk screened marking or bother checking the square pad, until
Phil Allison pointed it out in the first photo. The brain isn't
fading, but the eyesight is certainly going down the drain.
Assumption, the mother of all screwups, is also fully functional.

--
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: Thurs, Mar 31 2011 9:24 am
From: John Robertson

Jeff Liebermann wrote:
> On Thu, 31 Mar 2011 21:36:31 +1100, "Phil Allison" <phil_a@tpg.com.au>
> wrote:
>
>> ** With all those damn electros installed in reverse polarity, be a damn
>> site easier to alter the DC rails to suit - wouldn't it ??
>
> I thought you would be amused. I don't think that the IC's would
> appreciate the reversed power supply polarity.
>
> It took me about 45 minutes to tear down the XPS-200, replace 11 caps,
> reassemble, and test. It's now running an overnight burnin. I also
> fixed two of the other machines in about 30 minutes each (fewer caps
> to replace). What I found interesting was that the XPS-200 again
> worked for about a week with reverse polarized caps. My usual 24
> burnin is probably inadequate as I didn't bother doing a visual or
> thermal inspection after the burnin.
>
> Yes, I also learn from my mistakes.
>

An infra-red camera might be of use...or wet-touch each cap after its
been running a while (without exploding).

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 7 ==
Date: Thurs, Mar 31 2011 10:27 am
From: "larry moe 'n curly"

Jeff Liebermann wrote:
>
> Out of about 7 machines, I
> managed to reverse the caps on 4 of them. All had the silk screened
> stripe marking the "+" end instead of the usual "-" end. I didn't see
> the "+" silk screened marking or bother checking the square pad, until
> Phil Allison pointed it out in the first photo.

BTW, not all Dell mobos are marked that way.

Do you mean you don't write a red dot next to the positive lead when
you remove each capacitor? :) I do that because I've come across
circuit boards that were marked wrong.

== 5 of 7 ==
Date: Thurs, Mar 31 2011 2:26 pm
From: Jeff Liebermann

On Thu, 31 Mar 2011 10:27:03 -0700 (PDT), "larry moe 'n curly"
<larrymoencurly@my-deja.com> wrote:

>Jeff Liebermann wrote:
>>
>> Out of about 7 machines, I
>> managed to reverse the caps on 4 of them. All had the silk screened
>> stripe marking the "+" end instead of the usual "-" end. I didn't see
>> the "+" silk screened marking or bother checking the square pad, until
>> Phil Allison pointed it out in the first photo.

>BTW, not all Dell mobos are marked that way.

Yep. This is the first time I've seen boards marked that way and I've
been dealing with PC's since the Apple ][.

>Do you mean you don't write a red dot next to the positive lead when
>you remove each capacitor? :) I do that because I've come across
>circuit boards that were marked wrong.

I usually take a photograph. For major repairs, such as laptops, I
also print the photo, and mark any parts I replace. However, I
haven't found it necessary to mark the capacitor polarity. I have run
into some that were marked backwards, but that was maybe 10 years ago.
More commonly, capacitors where the silk screened markings are UNDER
the capacitor, where they can't be seen. When I do mark something on
the board, I use a UV pen for the top, and whatever I have handy for
the bottom (which can't be seen).

Worst case are some video cards, where the annular ring around the
solder bad is so narrow, that any attempt to solder the pad will
result in a guaranteed solder bridge. These also tend to have no
visible polarity markings of any kind, which adds to the challenge.

The problem here was that these machines were mine, not my customers.
So, I simply ignored all of this, and blundered onward with no photos
or markings.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

== 6 of 7 ==
Date: Thurs, Mar 31 2011 2:38 pm
From: Jeff Liebermann

On Thu, 31 Mar 2011 09:24:40 -0700, John Robertson <spam@flippers.com>
wrote:

>An infra-red camera might be of use...or wet-touch each cap after its
>been running a while (without exploding).

I use a cheap IR thermometer with a bit of creative optics to narrow
the viewing angle, or a thermocouple thermometer. I need my finger
tips functional for playing piano, organ, synth, etc. What I found
odd on the GX-520 board with the backwards capacitors, was that they
did NOT become warm:
<http://groups.google.com/group/sci.electronics.repair/msg/feb66e8acd3d46a4>
I measured the temperature and the capacitors were the same
temperature as the surroundings. I would have expected them to get
warm, but apparently not. My guess(tm) is that the plastic insulator,
between the foil wraps and the aluminum case, is also a fair thermal
insulator. While the electrolyte is getting hot and boiling off
belching gasses, there is little heat transfer to the case.

If you haven't broken it and then fixed it, you don't understand it.

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

== 7 of 7 ==
Date: Thurs, Mar 31 2011 3:23 pm
From: "Phil Allison"

"Jeff Liebermann"
>
> I measured the temperature and the capacitors were the same
> temperature as the surroundings.

** As is usually the case when the reverse voltage is only 3.3 or 5 volts.

> I would have expected them to get warm, but apparently not.

** Not IME at such low voltages.

> My guess(tm) is that the plastic insulator,
> between the foil wraps and the aluminum case, is also a fair thermal
> insulator. While the electrolyte is getting hot and boiling off
> belching gasses, there is little heat transfer to the case.

** No way - boiling electrolyte would make the whole cap too hot to touch.
Electro caps are almost like living things - when faced with reverse
polarity, they try to re-form as reversed caps. There is a limit, of course
and much heat will be generated if the voltage is more than a few volts.

Anecdote:

The most alarming example of a reversed electro I ever came across was
inside a *new in carton* 300 watt per channel power amplifier made by Jands
Electronics here in Sydney (a model J600).

One of the two 8000uF, 80V filter chassis mount electros had been installed
in reverse in the factory but the darn thing actually worked for a few
minutes until the AC fuse blew. Some clear liquid was split round the
bottom of the case. On correcting the error - the thing worked OK. Of
course, it got a new cap from me.

Although the amp was new, it had apparently not been used in 8 or 9 years
since manufacture. So I rang Jands and gave them the serial number.
According to their records the particular amp had " gone missing" from the
factory and was never sold to any customer. An "inside job " was suspected.

My customer professed total innocence.....

..... Phil

==============================================================================
TOPIC: Braun 4737 shaver.
http://groups.google.com/group/sci.electronics.repair/t/aefcfa1575d5288b?hl=en
==============================================================================

== 1 of 3 ==
Date: Thurs, Mar 31 2011 8:24 am
From: "Ian Field"

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:imr3oh$2qi$1@dont-email.me...
>> It turns out that plugging in the charger only makes the
>> motor cut out when the batteries are fully charged --
>> which actually isn't a problem.
>
> Dr Land wins again... "We already know the answers -- we haven't asked the
> right questions."

There is another problem though - Braun didn't use old fashioned NiCds for
the fun of it, the NiMh cells aren't up to the motor's high current draw
while shaving.

I got about 5 shaves out of a charge - should be more than 15.

== 2 of 3 ==
Date: Thurs, Mar 31 2011 9:42 am
From: "William Sommerwerck"

> There is another problem though -- Braun didn't use old-fashioned
> NiCds for the fun of it. The NiMh cells aren't up to the motor's high
> current draw while shaving.
> I got about 5 shaves out of a charge - should be more than 15.

That doesn't make sense. Like nicads, NiMHs are capable of pumping a lot of
current.

Cells vary in capacity. You can buy NiMH AA cells with 2500 or 2700mAh
capacity. I don't think nicads have ever had that high a capacity.

== 3 of 3 ==
Date: Thurs, Mar 31 2011 9:50 am
From: "Ian Field"

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:in2asr$3ag$1@dont-email.me...
>> There is another problem though -- Braun didn't use old-fashioned
>> NiCds for the fun of it. The NiMh cells aren't up to the motor's high
>> current draw while shaving.
>> I got about 5 shaves out of a charge - should be more than 15.
>
> That doesn't make sense. Like nicads, NiMHs are capable of pumping a lot
> of
> current.
>
> Cells vary in capacity. You can buy NiMH AA cells with 2500 or 2700mAh
> capacity. I don't think nicads have ever had that high a capacity.

Problem is the NiMh cells get pretty warm under full load - obviously not
all of the rated 2400mAh is ending up in the motor.

==============================================================================
TOPIC: Toroidal mains Tx inrush limiter - retrofit
http://groups.google.com/group/sci.electronics.repair/t/da7ba841cd54d76f?hl=en
==============================================================================

== 1 of 4 ==
Date: Thurs, Mar 31 2011 9:44 am
From: Meat Plow

On Thu, 31 Mar 2011 20:55:20 +1100, Phil Allison wrote:

> What a BORING know nothing, fuckwit bullshit artist

Nice self-description.

--
Live Fast Die Young, Leave A Pretty Corpse

== 2 of 4 ==
Date: Thurs, Mar 31 2011 11:12 am
From: dplatt@radagast.org (Dave Platt)

>>> Then what causes my bulk eraser to shut off when it overheats
>>> -- then come back when it cools off?
>
>> That's a resettable *thermal* fuse, NOT a fuse designed for
>> overcurrent protection.
>
>I had always thought that at least some polyfuses /were/ resettable.

Polyfuses (in the sense of the term I've always heard used) are
self-resetting, unless you hit 'em so hard that you damage them.

They aren't designed for use at mains voltages/currents, though... at
least, I haven't seen any that are.

The self-resetting thermal "fuses" that you'd find in a bulk eraser or
similar "not intended for a 100% duty cycle - let it cool down!"
device are (I think) of the bimetallic type, somewhat akin to what you
would find in a traditional wall thermostat.

--
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 4 ==
Date: Thurs, Mar 31 2011 3:04 pm
From: "Phil Allison"

"Tim Schwartz"
>
> Also keep in mind as a possibility that the main filter caps are getting
> tired, and a bit leaky, so that if the amp has not been switched on for a
> week or 2, it might have abnormally high inrush current as the caps
> charge/form back up.

** This is rather fanciful thinking.

An inrush surge ( on a 240V supply) that will take out a T3.15 fuse has to
be in the order of 40 to 50 amps. Toroidal transformers in the range of 220
to 300 VA with rectifiers and filter cap banks will provide such surges
almost every time they are switched on.

> Lastly, the older 'spring wire' fuses seemed more tolerant of the inrush
> current

** Correct, but hard to find them in other than 3AG size and they are much
more expensive.

> compared to the modern chemically treated wire ones.

** Where did you hear this one ??

The ones I use are said to be made from "plated wire" - meaning a thick
tin plating over copper. Some are coil shaped and some are not.

> It would be helpful if you would mention the make and model of the product
> in your posts.

** Bloody oath it would.

What a colossal ASS Kook is for regularly leaving that crucial info out.

.... Phil

== 4 of 4 ==
Date: Thurs, Mar 31 2011 4:58 pm
From: Grant

On Thu, 31 Mar 2011 11:12:22 -0700, dplatt@radagast.org (Dave Platt) wrote:

>>>> Then what causes my bulk eraser to shut off when it overheats
>>>> -- then come back when it cools off?
>>
>>> That's a resettable *thermal* fuse, NOT a fuse designed for
>>> overcurrent protection.
>>
>>I had always thought that at least some polyfuses /were/ resettable.
>
>Polyfuses (in the sense of the term I've always heard used) are
>self-resetting, unless you hit 'em so hard that you damage them.
>
>They aren't designed for use at mains voltages/currents, though... at
>least, I haven't seen any that are.

Me neither, other thing with polyfuses is that there's approx 2:1 current
difference between trigger point and hold point. I have 16V and 30V poly-
fuses here, generally for 12V or 24V SLA battery powered gear.
>
>The self-resetting thermal "fuses" that you'd find in a bulk eraser or
>similar "not intended for a 100% duty cycle - let it cool down!"
>device are (I think) of the bimetallic type, somewhat akin to what you
>would find in a traditional wall thermostat.

Some are the same thing as used in clothes dryer for thermostat, 100% duty
cycle for years on end ;) Lower temperature for thermostat and a higher
temp one for overheat safety cutout.

Grant.

==============================================================================
TOPIC: Please Visit:
http://groups.google.com/group/sci.electronics.repair/t/0574cb4adae6e901?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Mar 31 2011 12:38 pm
From: "mr.jak"

=================================
Explore & discover & be convinced that ISLAM is the truth! ...
Please Visit:
http://www.beconvinced.com

==============================================================================
TOPIC: Magnavox ZV450MW8A Remote Control Fix?
http://groups.google.com/group/sci.electronics.repair/t/c88c8c3007ad7b2b?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Mar 31 2011 4:06 pm
From: "Michael A. Terrell"

PeterD wrote:
>
> On 3/30/2011 8:07 PM, Michael A. Terrell wrote:
> >
> > PeterD wrote:
> >>
> >> On 3/29/2011 8:25 AM, Michael A. Terrell wrote:
> >>>
> >>> PeterD wrote:
> >>>>
> >>>> On 3/28/2011 1:56 PM, Michael A. Terrell wrote:
> >>>>>
> >>>>> Guv Bob wrote:
> >>>>>>
> >>>>>> I have had this DVD/VCR combo unit for over 3 years now, and would like to find out if anyone has found a 3rd party remote control that can be used with it, or if the factory has a remote with upgraded software.
> >>>>>>
> >>>>>> The device is top quality and the manual is excellent, but the remote is so complicated and non-intuitive that if you don't use it every day, you have to go back to the manual, even after this long time.
> >>>>>>
> >>>>>> The manual does leave out some basic steps -- like how to set the record speed (which they call "mode"). I'm fairly good with electronics (servicing industrial electronics is my business) and took me a good year before I could make basic settings without looking it up.
> >>>>>>
> >>>>>> Most of the features can't be done from the device and must be done via the remote control which is cryptic. It has way too many buttons, even for a combo unity, and has tiny labels that can't be read in a darkened room. If you hit a wrong button, sometimes it is impossible to figure out how to return the device to normal use without digging out the manual again. My manual is well worn and has many notes scribbled in it now.
> >>>>>>
> >>>>>> One problem is that when you are using the timer, you have to turn the device off and on with a button other than the ON/OFF button. If your lovely wife comes in and used ON/OFF, it disables the timer, and must be reset again with the special non-ON/OFF button.
> >>>>>>
> >>>>>> It is a real shame that such a fine device from a good manufacturer has such a poor user interface. A better designed remote would completely change the usability.
> >>>>>
> >>>>>
> >>>>> Wrong newsgroup. This is a test equipment newsgroup. You want
> >>>>> news:sci.electronics.repair.
> >>>>>
> >>>>>
> >>>>
> >>>> Michael... Careful you posted your reply to the wrong groups too!<g>
> >>>
> >>>
> >>> No. I added the proper group.
> >>>
> >>>
> >>
> >> I had to read that twice before I realized what you meant...<g> So you
> >> added SER to help the OP out. Sure left me confused!
> >
> >
> > Get used to it. It will happen more and more as you age. :(
> >
>
> Damn, not what I wanted to hear!

Me, either. The VA put me on Insulin and Terazosin today. Like Art
Linkletter used to say, "Old age isn't for sissies!"

--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

==============================================================================
TOPIC: How-To: Common Cause Of Flat Panel PS Failure
http://groups.google.com/group/sci.electronics.repair/t/ff5b6703ec041dcc?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Mar 31 2011 4:20 pm
From: "Michael A. Terrell"

Bob Villa wrote:
>
> On Mar 7, 9:13 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
> wrote:
> > Bob Villa wrote:
> >
>
> > > Do YOU even know how to read? I put this out there...if you want to
> > > add to it from your experience go to it. There are people who are just
> > > trying to save some money and fix things themselves. Lighten up...I
> > > don't need to belong to your fucking club!
> >
> > Posting half assed information helps no one, and bad electrolytics in
> > power supplies have been a problem since the '20s. Also, no one needs
> > your childish rants. There are enough crybabies who pop into the group
> > and think they are a genius, without you.
>
> Hey Mike when can I expect this PSU to fail...a few years from now?
> Thanks for your gracious responses.

When can you post a real question?

--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

== 2 of 2 ==
Date: Thurs, Mar 31 2011 4:38 pm
From: Bob Villa

On Mar 31, 6:20 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

>
> > Hey Mike when can I expect this PSU to fail...a few years from now?
> > Thanks for your gracious responses.
>
> When can you post a real question?
>
> --
> You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
> Teflon coated.

Alas, the mastertech doesn't understand sarcasm.

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