Hi everyone,


I'm sorry for my low level knowledge about electronics. I hope this group
can help me. I use a compaq Tower PC from 1998.

It still functioned admirably, but I had connected a fan to one of the 4
cable (red black black yellow) plugs
which also go into hard disk and cdrom drives, using wires I put loosely
inserted into the plug.

Unfortunately, I caused in this plug a short circuit by pulling the loose
wires which connected
this fan to the plug and had the red and black ones touch each other for a
second.

However stupid this may be, I first thought no damage was done to the power
supply. However, the ATX motherboard power switch did not start the computer
no more. I thought the motherboard was gone as well by then.

I bought a new power supply, and the problem is over, for now.

I still hope I can fix the first, older power supply, because the new power
supply
stated on the box that there was protection against short circuits.

Is it possible that only the small fuse in the old power supply has blown,
or that I can repair the power supply ? The short circuit i caused only
lasted for a second maybe.

MTIA,

peter

Yes, this is possible that all that is wrong is an internally blown fuse.

Bob
wrote in message ...
Hi everyone,


I'm sorry for my low level knowledge about electronics. I hope this group
can help me. I use a compaq Tower PC from 1998.

It still functioned admirably, but I had connected a fan to one of the 4
cable (red black black yellow) plugs
which also go into hard disk and cdrom drives, using wires I put loosely
inserted into the plug.

Unfortunately, I caused in this plug a short circuit by pulling the loose
wires which connected
this fan to the plug and had the red and black ones touch each other for a
second.

However stupid this may be, I first thought no damage was done to the
power
supply. However, the ATX motherboard power switch did not start the
computer
no more. I thought the motherboard was gone as well by then.

I bought a new power supply, and the problem is over, for now.

I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.

Is it possible that only the small fuse in the old power supply has blown,
or that I can repair the power supply ? The short circuit i caused only
lasted for a second maybe.

MTIA,

peter

"Bob Shuman" writes:

Yes, this is possible that all that is wrong is an internally blown fuse.

Try replacing the fuse. But if it blows again, then it's not worth fixing
the power supply, especially given your level of experience.

WARNING: LETHAL VOLTAGES INSIDE WHICH CAN REMAIN AFTER UNPLUGGING!
Take care.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Bob
wrote in message ...
Hi everyone,


I'm sorry for my low level knowledge about electronics. I hope this group
can help me. I use a compaq Tower PC from 1998.

It still functioned admirably, but I had connected a fan to one of the 4
cable (red black black yellow) plugs
which also go into hard disk and cdrom drives, using wires I put loosely
inserted into the plug.

Unfortunately, I caused in this plug a short circuit by pulling the loose
wires which connected
this fan to the plug and had the red and black ones touch each other for a
second.

However stupid this may be, I first thought no damage was done to the
power
supply. However, the ATX motherboard power switch did not start the
computer
no more. I thought the motherboard was gone as well by then.

I bought a new power supply, and the problem is over, for now.

I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.

Is it possible that only the small fuse in the old power supply has blown,
or that I can repair the power supply ? The short circuit i caused only
lasted for a second maybe.

MTIA,

peter

Hello,

"Sam Goldwasser" schreef in bericht
...
"Bob Shuman" writes:

Yes, this is possible that all that is wrong is an internally blown
fuse.

Try replacing the fuse. But if it blows again, then it's not worth fixing
the power supply, especially given your level of experience.

WARNING: LETHAL VOLTAGES INSIDE WHICH CAN REMAIN AFTER UNPLUGGING!
Take care.
Bob
wrote in message ...
Hi everyone,


I'm sorry for my low level knowledge about electronics. I hope this
group
can help me. I use a compaq Tower PC from 1998.

It still functioned admirably, but I had connected a fan to one of the
4
cable (red black black yellow) plugs
which also go into hard disk and cdrom drives, using wires I put
loosely
inserted into the plug.

Unfortunately, I caused in this plug a short circuit by pulling the
loose
wires which connected
this fan to the plug and had the red and black ones touch each other
for a
second.

However stupid this may be, I first thought no damage was done to the
power
supply. However, the ATX motherboard power switch did not start the
computer
no more. I thought the motherboard was gone as well by then.

I bought a new power supply, and the problem is over, for now.

I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.

Is it possible that only the small fuse in the old power supply has
blown,
or that I can repair the power supply ? The short circuit i caused
only
lasted for a second maybe.

MTIA,

peter

Hello,

Thanks for the feedback. I would not know where to find a replacement fuse,
given I'm living far away from shops where they sell them. I bought a second
power supply and will try to find a fuse later on.

This Compaq power supply was from 1998, I hope back then it was also
designed to cope with short circuits like the new one I bought now. I
suspect the red-black wires transport 12V supply, and the yellow one 5V (?).


Thanks again,

Peter

wrote in message ...
Hi everyone,
I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.


In my experience, any fuse(s) located inside the SMPS RARELY if EVER protect
the circuit from a short condition... there's pretty much always something
else fried in the unit. Switch-mode power supplies are amazingly cheap for
what they provide, which is very well regulated, efficient DC power. They
are also very very time consuming to diagnose and repair. As such, the
general concensus in the repair industry is to throw it out and buy another
one. I believe you made the right choice. As another poster has suggested,
try replacing the fuse, if there is one, then throw it in the bin.

Dave

Hello,

Thanks for the feedback. I would not know where to find a replacement fuse,
given I'm living far away from shops where they sell them. I bought a second
power supply and will try to find a fuse later on.

This Compaq power supply was from 1998, I hope back then it was also
designed to cope with short circuits like the new one I bought now. I
suspect the red-black wires transport 12V supply, and the yellow one 5V (?).


Thanks again,

Peter






You got 10 years out of it, that's a pretty good run. I wouldn't bother
fixing it myself, you can salvage some interesting parts from them if
you're into that.

"Dave" schreef in bericht
news:cyAZj.3685$Yp.3016@edtnps92...
wrote in message ...
Hi everyone,
I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.


In my experience, any fuse(s) located inside the SMPS RARELY if EVER
protect
the circuit from a short condition... there's pretty much always something
else fried in the unit. Switch-mode power supplies are amazingly cheap
for
what they provide, which is very well regulated, efficient DC power. They
are also very very time consuming to diagnose and repair. As such, the
general concensus in the repair industry is to throw it out and buy
another
one. I believe you made the right choice. As another poster has
suggested,
try replacing the fuse, if there is one, then throw it in the bin.

Dave



Hi Dave, and thanks.

I must say, thinking of what could go wrong now, I fear - knowing nothing
about power supplies or their electronics - that if I replace the fuze and
something else in de unit is also damaged, it may well be that the actual
voltage produced by the damaged power supply would maybe exceed what the
motherboard of my pc could cope with. I would maybe be happy replacing just
the fuze, but the unit could cause more damage. I think I will stay with the
new power supply unit.

Thanks again to all,

Peter

Hi Dave, and thanks.

I must say, thinking of what could go wrong now, I fear - knowing nothing
about power supplies or their electronics - that if I replace the fuze and
something else in de unit is also damaged, it may well be that the actual
voltage produced by the damaged power supply would maybe exceed what the
motherboard of my pc could cope with. I would maybe be happy replacing just
the fuze, but the unit could cause more damage. I think I will stay with the
new power supply unit.

Thanks again to all,

Peter




If you know nothing about power supplies, then stay out of it, as others
have mentioned, a switchmode PSU is no place for a beginner. Even as an
experienced tech, I loath working on PC power supplies, I've failed on
many more than I've succeeded in repairing.

"Dave" schreef in bericht
news:cyAZj.3685$Yp.3016@edtnps92...
wrote in message ...
Hi everyone,
I still hope I can fix the first, older power supply, because the new
power
supply
stated on the box that there was protection against short circuits.


In my experience, any fuse(s) located inside the SMPS RARELY if EVER
protect
the circuit from a short condition... there's pretty much always something
else fried in the unit. Switch-mode power supplies are amazingly cheap
for
what they provide, which is very well regulated, efficient DC power. They
are also very very time consuming to diagnose and repair. As such, the
general concensus in the repair industry is to throw it out and buy
another
one. I believe you made the right choice. As another poster has
suggested,
try replacing the fuse, if there is one, then throw it in the bin.

Dave

Hi Dave, and thanks.

I must say, thinking of what could go wrong now, I fear - knowing nothing
about power supplies or their electronics - that if I replace the fuze and
something else in de unit is also damaged, it may well be that the actual
voltage produced by the damaged power supply would maybe exceed what the
motherboard of my pc could cope with. I would maybe be happy replacing just
the fuze, but the unit could cause more damage. I think I will stay with the
new power supply unit.

Thanks again to all,

Peter

Hi!

Thanks for the feedback. I would not know where to find a replacement
fuse, given I'm living far away from shops where they sell them.

Most every computer power supply I've seen has used an AGC (glass) type
fuse. It looks like a tube with glass in the center and metal at the ends.
The rating and voltage will be printed (stamped) on one of the metal ends.

This Compaq power supply was from 1998, I hope back then it was
also designed to cope with short circuits like the new one I bought
now.

Normally a computer power supply will simply "crowbar" its outputs and shut
down without damage when a short circuit comes up. That's assuming that the
power supply is in otherwise good health with no components that are
starting to fail or change characteristics.

I suspect the red-black wires transport 12V supply, and the
yellow one 5V (?).

The red wire is +5 volts. The yellow wire is +12 volts. Each black wire is a
ground.

William

wrote:

I suspect the red-black wires transport 12V supply, and the yellow one 5V (?).

Opposite. Red 5V, yellow 12V, black ground.

On Fri, 23 May 2008 14:54:32 +0200, put finger to keyboard
and composed:

This Compaq power supply was from 1998, I hope back then it was also
designed to cope with short circuits like the new one I bought now. I
suspect the red-black wires transport 12V supply, and the yellow one 5V (?).

A normal AT/ATX PSU has +12V on the yellow and +5V on the red. Be
aware that certain 3rd party PC manufacturers (eg Apricot)
intentionally wired these the other way around in an attempt to force
the user to buy replacement parts from them.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 23 mayo, 19:23, wrote:
.. I would maybe be happy replacing just
the fuze, but the unit could cause more damage. I think I will stay with the
new power supply unit.

Thanks again to all,

Peter

I'd just like to echo what other posters like Dave and James have
pointed out - repairing a 10 year old power supply is not worth the
trouble, especially for a beginner.

even if repair were feasible, the parts would exceed the cost /value
of the whole thing! I suggest going to your local dump or fleamarket,
those places are full of this stuff for next to nothing or free. you
could probably pick up a better PC than your 1998 model while you're
there!

oh yeah, and your local freecycle list is anpther good place for free
stuff like this if you want machines to 'practise' on.
-B

Franc Zabkar writes:

On Fri, 23 May 2008 14:54:32 +0200, put finger to keyboard
and composed:

This Compaq power supply was from 1998, I hope back then it was also
designed to cope with short circuits like the new one I bought now. I
suspect the red-black wires transport 12V supply, and the yellow one 5V (?).

A normal AT/ATX PSU has +12V on the yellow and +5V on the red. Be
aware that certain 3rd party PC manufacturers (eg Apricot)
intentionally wired these the other way around in an attempt to force
the user to buy replacement parts from them.

How many lawsuits did they have?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

On 26 May 2008 19:14:12 -0400, Sam Goldwasser
put finger to keyboard and composed:

Franc Zabkar writes:

A normal AT/ATX PSU has +12V on the yellow and +5V on the red. Be
aware that certain 3rd party PC manufacturers (eg Apricot)
intentionally wired these the other way around in an attempt to force
the user to buy replacement parts from them.

How many lawsuits did they have?

I recently offered my old Apricot PSUs to an Apricot enthusiast for
free. He hasn't yet responded to my email. Maybe that's a bad sign.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.