Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old July 14th 16, 08:10 PM posted to sci.electronics.repair
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Default Could this be power supply related?

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric

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Old July 14th 16, 09:27 PM posted to sci.electronics.repair
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Default Could this be power supply related?

In article ,
says...

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric



Some of the computers have been known to have capacitors that go bad
after a few years. The classic symptom is the computer comes on when
hot.

Look at the larger capacitors that have leads going through the board.
If the top of them is rounded off like a dome they are bad. They should
be flat. This could be on the motherboard or video board.


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Old July 14th 16, 10:12 PM posted to sci.electronics.repair
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Default Could this be power supply related?

On Thursday, July 14, 2016 at 4:27:21 PM UTC-4, Ralph Mowery wrote:
In article ,
says...

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric



Some of the computers have been known to have capacitors that go bad
after a few years. The classic symptom is the computer comes on when
hot.

Look at the larger capacitors that have leads going through the board.
If the top of them is rounded off like a dome they are bad. They should
be flat. This could be on the motherboard or video board.

Could be in the power supply too. Check all caps on the 5V or 3.3V lines.

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Old July 15th 16, 12:22 AM posted to sci.electronics.repair
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Posts: 1,243
Default Could this be power supply related?

On 7/14/2016 2:12 PM, wrote:
On Thursday, July 14, 2016 at 4:27:21 PM UTC-4, Ralph Mowery wrote:
In article ,
says...

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric



Some of the computers have been known to have capacitors that go bad
after a few years. The classic symptom is the computer comes on when
hot.

Look at the larger capacitors that have leads going through the board.
If the top of them is rounded off like a dome they are bad. They should
be flat. This could be on the motherboard or video board.

Could be in the power supply too. Check all caps on the 5V or 3.3V lines.

Put an oscilloscope on all the power supply lines and see if they look
good. A typical voltmeter won't always see the problem. You can read
5V on the voltmeter and have horrible spikes on the line.
Don't forget 5VSB. I've had several systems where the cap on the 5V
standby supply went. Nothing else would run without it.
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Old July 15th 16, 12:18 PM posted to sci.electronics.repair
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Default Could this be power supply related?

On Thursday, July 14, 2016 at 3:05:35 PM UTC-4, wrote:
I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric


Since you've already ordered a new power supply I wouldn't go any further until that's installed. If the supply is sluggish or inop when cold, it most likely has high esr electrolytics. Even when warm enough to allow function, they still allow sag and ripple on the outputs which can upset whatever is connected to it. Good chance everything gets fixed with the new supply..



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Old July 15th 16, 07:12 PM posted to sci.electronics.repair
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Default Could this be power supply related?

On Fri, 15 Jul 2016 04:18:11 -0700 (PDT), wrote:

On Thursday, July 14, 2016 at 3:05:35 PM UTC-4, wrote:
I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?
Eric


Since you've already ordered a new power supply I wouldn't go any further until that's installed. If the supply is sluggish or inop when cold, it most likely has high esr electrolytics. Even when warm enough to allow function, they still allow sag and ripple on the outputs which can upset whatever is connected to it. Good chance everything gets fixed with the new supply.

Thanks everyone for the replies. It seems weird to me that the video
output fails after quite some time, maybe as long as 36 hours. I
looked at the caps on the video card and none have any obvious bulging
or leaking. So I'm just gonna shop around for video cards and when the
new power supply is installed if the video out fails again then I'll
get the card I want.
Eric
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Old July 16th 16, 08:02 PM posted to sci.electronics.repair
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Default Could this be power supply related?

On Thu, 14 Jul 2016 12:10:51 -0700, wrote:

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?


You're assuming that the time in fridge is what made it work when on
other occasions waiting itself had an effect.

Anyhow, I once got 3 moderately old video cards for 10, inc. shipping,
probably on ebay. Each failed after about 3 years but I'd rather
start with a spare old card than buy a fancy one not being sure it's
the problem. You could also try plugging in another monitor when
yours isn't working.

I don't really think the PSU is affecting the picture, but you do have
a point that getting another video card would narrow things down. So
will the new ps when it comes.

BTW, paragraphs would make your post much more legible.
Eric

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Old July 16th 16, 10:56 PM posted to sci.electronics.repair
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Default Could this be power supply related?

On Sat, 16 Jul 2016 15:02:01 -0400, Micky
wrote:

On Thu, 14 Jul 2016 12:10:51 -0700, wrote:

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?


You're assuming that the time in fridge is what made it work when on
other occasions waiting itself had an effect.

Anyhow, I once got 3 moderately old video cards for 10, inc. shipping,
probably on ebay. Each failed after about 3 years but I'd rather
start with a spare old card than buy a fancy one not being sure it's
the problem. You could also try plugging in another monitor when
yours isn't working.

I don't really think the PSU is affecting the picture, but you do have
a point that getting another video card would narrow things down. So
will the new ps when it comes.

BTW, paragraphs would make your post much more legible.
Eric

OK, I'll try paragraphs.

I am not assuming that the fridge treatment made the card work, but I
think it may have. I just knew that it took some time being off for it
to work again and I didn't know if cooling might have made it work
again. I wrote what I did trying to be thorough.


Eric
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Old July 17th 16, 12:23 PM posted to sci.electronics.repair
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Posts: 642
Default Could this be power supply related?

On Sat, 16 Jul 2016 14:56:40 -0700, wrote:

On Sat, 16 Jul 2016 15:02:01 -0400, Micky
wrote:

On Thu, 14 Jul 2016 12:10:51 -0700,
wrote:

I have a computer with a funky power supply. It won't turn on until
something in it is warm enough. I have ordered another but a new
problem has cropped up in this computer. The monitor said there was no
signal even though it was connected to the computer. Thinking it might
be dirty contacts I removed the video card and the monitor cable,
cleaned the contacts, and plugged everything back in. No joy. I
unplugged the computer and let it sit about an hour. Plugged it back
in, tried turning it on but had to wait a few minutes for the power
supply to start fully functioning and when it did the computer worked
properly and the monitor had a picture. I left the computer on for
several days and everything worked fine until this morning when once
again the monitor reported no signal and once again no picture. So I
removed power from the computer and removed the video card. I put the
card in the fridge for abou 1/2 hour. Then I put the card back in the
computer, plugged the computer back in, waited the few minutes again,
and now it all works fine again. So, should I start shopping for a
video card too? Could the flaky power supply be affecting the video
card too?


You're assuming that the time in fridge is what made it work when on
other occasions waiting itself had an effect.

Anyhow, I once got 3 moderately old video cards for 10, inc. shipping,
probably on ebay. Each failed after about 3 years but I'd rather
start with a spare old card than buy a fancy one not being sure it's
the problem. You could also try plugging in another monitor when
yours isn't working.

I don't really think the PSU is affecting the picture, but you do have
a point that getting another video card would narrow things down. So
will the new ps when it comes.

BTW, paragraphs would make your post much more legible.
Eric

OK, I'll try paragraphs.

I am not assuming that the fridge treatment made the card work, but I
think it may have. I just knew that it took some time being off for it
to work again and I didn't know if cooling might have made it work
again. I wrote what I did trying to be thorough.


That's a good practice. Better than medium, and far better than the
opposite where people leave even important things out.


Eric



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