Powersupply tests

  • Thread starter Thread starter John
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J

John

Hi,
I have 3 psu`s which appear to be dead. How do I go about testing them.
I attached a power lead to them and applied power but am not getting any 5v
output from the disk supplies. What tests would confirm their
status........repairable or dead.? I have tested the fuse on one and it is
ok. Is the psu active without a motherboard attached or is there some
circuitry which disables the outputs if no mobo is present?
John
 
John said:
I have 3 psu`s which appear to be dead. How do I go about testing them.
I attached a power lead to them and applied power but am not getting any 5v
output from the disk supplies. What tests would confirm their
status........repairable or dead.? I have tested the fuse on one and it is
ok. Is the psu active without a motherboard attached or is there some
circuitry which disables the outputs if no mobo is present?
Click to expand...

I am assuming they are ATX. To test ATX PSUs:

First, disconnect everything from the power supply (including MB.) Plug
AC cord into the rear of the PS. IF the PS has its own rocker on/off
switch, turn it ON. There should be +5v on pin 9 of the 20 pin connector
(+5vsb, usually a violet wire.) There should be >0.8v on pin 14 (PS-ON,
usually a green wire.) This is from an internal pull-up to the +5vsb.

Connect PS power leads to 1 or 2 IDE HDs (for a load). Jumper pin 14
(PS-ON) to pin 13 (ground, black wire.) At this point, fan in PS should
start spinning, drives should spin, and + 5/12v, -5/12v, +3.3v, and
+5vsb should be present at 20 pin connector.

Disconnecting pin 14-13 jumper should turn supply back off.
 
Hi,
I have 3 psu`s which appear to be dead. How do I go about testing them.
I attached a power lead to them and applied power but am not getting any 5v
output from the disk supplies. What tests would confirm their
status........repairable or dead.? I have tested the fuse on one and it is
ok. Is the psu active without a motherboard attached or is there some
circuitry which disables the outputs if no mobo is present?
John
Click to expand...
You can pick up an ATX power supply tester for $10 to $20 at a local
computer store like Comp USA...
Glenn M

A GREAT DAY FOR FREEDOM...Pink Floyd
 
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