Would you risk it - PSU

Hi there,
Got a PC here from a customer, fails to power on, replacement PSU
doesn't help. It's not exactly new, and I recommended buying a new base
unit and slaving the old disk in that (disk is fine and data is there)
customer still went for the repair option, which is going to set him
back only £50 less than a new base unit.
Anyway, the existing psu appears to work ok, but I don't have a tester.
When the new mobo arrives should I try it with that or use a new one in
case that was involved in the damage to the mobo.
Quote for repair included a processor as well as mobo, but will try the
mobo only first - (socket 478 are getting hard to find)
thanks simon

"Simon" wrote in message
...
Hi there,
Got a PC here from a customer, fails to power on, replacement PSU
doesn't help. It's not exactly new, and I recommended buying a new base
unit and slaving the old disk in that (disk is fine and data is there)
customer still went for the repair option, which is going to set him
back only £50 less than a new base unit.
Anyway, the existing psu appears to work ok, but I don't have a tester.
When the new mobo arrives should I try it with that or use a new one in
case that was involved in the damage to the mobo.

You have not ruled out the PSU as being the cause of the first MB to fry?
Then your askin for trouble.


Quote for repair included a processor as well as mobo, but will try the
mobo only first - (socket 478 are getting hard to find)
thanks simon

Simon wrote:

Got a PC here from a customer, fails to power on, replacement PSU
doesn't help. It's not exactly new, and I recommended buying a new base
unit and slaving the old disk in that (disk is fine and data is there)
customer still went for the repair option, which is going to set him
back only £50 less than a new base unit.
Anyway, the existing psu appears to work ok, but I don't have a tester.

You have customers but don't have anything to test power supplies, like
a voltage meter? Isn't that irresponsible?

You have not ruled out the PSU as being the cause of the first MB to fry?
Then your askin for trouble.


Agreed. PSUs are so trouble-prone that there is no way I would use an
existing PSU to power a new mainboard if there was ANY question at all about
what caused the mainboard to fail.

Or to look at it another way, it's a roll of the dice. You can put a new
mainboard on the original PSU and hope that it's OK. If luck is not with
you, you now owe the customer a new mainboard (a SECOND new mainboard), a
new PSU and possibly other components as well (who says a possibly bad PSU
will just take out the mainboard this time around?)

Plus, how many times do you want to FIX this one system? Do it right the
first time and move on. -Dave

Simon wrote:
Hi there,
Got a PC here from a customer, fails to power on, replacement PSU
doesn't help. It's not exactly new, and I recommended buying a new base
unit and slaving the old disk in that (disk is fine and data is there)
customer still went for the repair option, which is going to set him
back only £50 less than a new base unit.
Anyway, the existing psu appears to work ok, but I don't have a tester.

You can't workout where to buy a multimeter? Are you providing hardware
warranty? What statutes are you legally required to abide by in your
country's consumer relations laws?

When the new mobo arrives should I try it with that or use a new one in
case that was involved in the damage to the mobo.
Quote for repair included a processor as well as mobo, but will try the
mobo only first - (socket 478 are getting hard to find)
thanks simon


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Many people around the world are waiting for a marrow transplant. Please
volunteer to be a marrow donor and literally save someone's life:
http://www.abmdr.org.au/
http://www.marrow.org/

Mike T. wrote:
You have not ruled out the PSU as being the cause of the first MB to fry?
Then your askin for trouble.


Agreed. PSUs are so trouble-prone that there is no way I would use an
existing PSU to power a new mainboard if there was ANY question at all about
what caused the mainboard to fail.

Or to look at it another way, it's a roll of the dice. You can put a new
mainboard on the original PSU and hope that it's OK. If luck is not with
you, you now owe the customer a new mainboard (a SECOND new mainboard), a
new PSU and possibly other components as well (who says a possibly bad PSU
will just take out the mainboard this time around?)

Plus, how many times do you want to FIX this one system? Do it right the
first time and move on. -Dave


cheers, daft question I agree. And to the others, yes I do have a
multimeter.
simon

Simon wrote:
Hi there,
Got a PC here from a customer, fails to power on, replacement PSU
doesn't help. It's not exactly new, and I recommended buying a new base
unit and slaving the old disk in that (disk is fine and data is there)
customer still went for the repair option, which is going to set him
back only £50 less than a new base unit.
Anyway, the existing psu appears to work ok, but I don't have a tester.
When the new mobo arrives should I try it with that or use a new one in
case that was involved in the damage to the mobo.
Quote for repair included a processor as well as mobo, but will try the
mobo only first - (socket 478 are getting hard to find)
thanks simon

Without test gear, I'd go for a new power supply.

Then, find yourself some gear that you can test with,
for future customers.

Tomshardware built themselves a load box. I've built one a
little less fancy for myself. About $100 worth of resistors,
wire, a fan for cooling, can make a nice load box, that
will draw a representative load from an ATX PSU. Then,
connect your multimeter to the load box and measure the
voltage of the rails. If the rails meet spec (5% or whatever
is printed on the PSU label), then the PSU passes. Any weird
smells, sights or sounds, while the PSU is on the tester,
then into the rubbish it goes.

http://www.tomshardware.com/2002/10/...ing/page4.html

A PSU could damage your tester. You can occasionally use your
multimeter to verify the resistors are still OK on the load
box. You measure the resistors when the load box is new, and
then you know what the resistor values are later, when you
suspect the load box has been damaged.

The products offered as "testers" are a bit on the weak
side technically. This "tester" only shows the presence
of power, but doesn't give you any details. A load
box and a multimeter is a much better way to go. I
wouldn't even want one of these if it was free. There
are some even worse ones, that only load one rail of
the multiple rails on a supply.

http://www.dansdata.com/quickshot018.htm

There are probably professional testers, that can
apply a load under programmable control, but that is
overkill for what you want. It is too bad there don't
seem to be any (popular) cheap load boxes for sale. At
least I haven't seen any good ones in a quick search.
You'll need to know Ohms law, if you want to build
one yourself (i.e. know a little bit about resistors,
electricity, power rating etc).

Paul

Simon wrote:
Mike T. wrote:
You have not ruled out the PSU as being the cause of the first MB to
fry?
Then your askin for trouble.


Agreed. PSUs are so trouble-prone that there is no way I would use an
existing PSU to power a new mainboard if there was ANY question at all
about what caused the mainboard to fail.

Or to look at it another way, it's a roll of the dice. You can put a
new mainboard on the original PSU and hope that it's OK. If luck is
not with you, you now owe the customer a new mainboard (a SECOND new
mainboard), a new PSU and possibly other components as well (who says
a possibly bad PSU will just take out the mainboard this time around?)

Plus, how many times do you want to FIX this one system? Do it right
the first time and move on. -Dave

cheers, daft question I agree. And to the others, yes I do have a
multimeter.
simon

On your own website you talk about PSUs taking the rest of the system
with them. Unless there are blatantly bad caps on the old (failed)
motherboard, I'd follow your instincts and replace the PSU.

Ari

--
spammage trappage: remove the underscores to reply
Many people around the world are waiting for a marrow transplant. Please
volunteer to be a marrow donor and literally save someone's life:
http://www.abmdr.org.au/
http://www.marrow.org/