Trying to test PS

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Tuner

I'm struggling with attempting to diagnose problems in a "switching" no-name
power supply. I've already replaced it in the computer, but figured I could
add to my knowledge by testing the actual vs. claimed voltage on the various
supply wires after it was removed.. I've got the thing on my workbench, and
can't seem to get ANY readings save for the 5V line in the main ATX
connector. Do I need a jumper somewhere to simulate an installed
environment? Maybe it's just toast, but I suspect (since I've not done this
type of analysis before) that I'm missing something obvious.

Save the warnings, I have no intention of poking around INSIDE the supply,
but would like to learn more about what to expect from the output.

TIA

Tuner
 
Tuner said:
I'm struggling with attempting to diagnose problems in a "switching" no-name
power supply. I've already replaced it in the computer, but figured I could
add to my knowledge by testing the actual vs. claimed voltage on the various
supply wires after it was removed.. I've got the thing on my workbench, and
can't seem to get ANY readings save for the 5V line in the main ATX
connector. Do I need a jumper somewhere to simulate an installed
environment? Maybe it's just toast, but I suspect (since I've not done this
type of analysis before) that I'm missing something obvious.
Click to expand...

You get a reading on which 5V line? standby?

First, you generally do need a load on it (although some will power up
alone) and I keep a junker hard drive for that purpose. Just plug it into
one of the normal hard drive connectors.

Second, did you jumper it 'on'? You need to connect pin 14 (green), "power
on", to ground (any of [black] pins 13, 15, 16, 17). I find that a bent
paper clip in the socket pins works fine.
 
Yes, you're precisely correct - I'm getting a reading on the standby line.
It all makes sense now - Thanks!

Tuner

David Maynard said:
Tuner said:
I'm struggling with attempting to diagnose problems in a "switching"
no-name power supply. I've already replaced it in the computer, but
figured I could add to my knowledge by testing the actual vs. claimed
voltage on the various supply wires after it was removed.. I've got the
thing on my workbench, and can't seem to get ANY readings save for the 5V
line in the main ATX connector. Do I need a jumper somewhere to simulate
an installed environment? Maybe it's just toast, but I suspect (since
I've not done this type of analysis before) that I'm missing something
obvious.
Click to expand...

You get a reading on which 5V line? standby?

First, you generally do need a load on it (although some will power up
alone) and I keep a junker hard drive for that purpose. Just plug it into
one of the normal hard drive connectors.

Second, did you jumper it 'on'? You need to connect pin 14 (green), "power
on", to ground (any of [black] pins 13, 15, 16, 17). I find that a bent
paper clip in the socket pins works fine.
Click to expand...
 
....>I'm struggling with attempting to diagnose problems in a "switching" no-name
....>power supply. I've already replaced it in the computer, but figured I could
....>add to my knowledge by testing the actual vs. claimed voltage on the various
....>supply wires after it was removed.. I've got the thing on my workbench, and
....>can't seem to get ANY readings save for the 5V line in the main ATX
....>connector. Do I need a jumper somewhere to simulate an installed
....>environment? Maybe it's just toast, but I suspect (since I've not done this
....>type of analysis before) that I'm missing something obvious.
....>
....>Save the warnings, I have no intention of poking around INSIDE the supply,
....>but would like to learn more about what to expect from the output.
....>
....>TIA
....>
....>Tuner
....>==================
To test an ATX power supply:
Click to expand...
....>
....>---
....>Outgoing mail is certified Virus Free.
....>Checked by AVG anti-virus system (http://www.grisoft.com).
....>Version: 6.0.805 / Virus Database: 547 - Release Date: 12/3/2004
....>
Bud in FL
 
Second, did you jumper it 'on'? You need to connect pin 14 (green), "power
on", to ground (any of [black] pins 13, 15, 16, 17). I find that a bent
paper clip in the socket pins works fine.
Click to expand...

I did that once in order to add a second power supply to an old computer.
The original power supply was underpowered, and I had another unused one in
my junkpile - so rather than go to the expense of buying a higher wattage
PS, I just used the spare one and used the paper clip trick on it (actually
I soldered an insulated wire instead). Of course I had a full tower case, so
fitting the second PS in there was no problem. However, it would have been a
lot more difficult, if not impossible, with a mid-tower or smaller case.
 
Papa said:
Second, did you jumper it 'on'? You need to connect pin 14 (green), "power
on", to ground (any of [black] pins 13, 15, 16, 17). I find that a bent
paper clip in the socket pins works fine.
Click to expand...

I did that once in order to add a second power supply to an old computer.
The original power supply was underpowered, and I had another unused one in
my junkpile - so rather than go to the expense of buying a higher wattage
PS, I just used the spare one and used the paper clip trick on it (actually
I soldered an insulated wire instead).
Click to expand...

You could have simply run a wire from the green wire of the first power
supply to the green wire of the second supply.
 
You could have simply run a wire from the green wire of the first power
supply to the green wire of the second supply.
Click to expand...

And hope that the source current from the two supplies combined doesn't
exceed the sink current specification of the MB.
 
ric said:
And hope that the source current from the two supplies combined doesn't
exceed the sink current specification of the MB.
Click to expand...

I doubt it. I tried 3 different power supplies, and their Power_Good
currents varied from 0.1 mA (poorly made no-name) to 0.6mA (well made
no-name). An Antec (Channelwell) measured 0.5 mA.
 
I doubt it. I tried 3 different power supplies, and their Power_Good
currents varied from 0.1 mA (poorly made no-name) to 0.6mA (well made
no-name). An Antec (Channelwell) measured 0.5 mA.
Click to expand...

???

You referred to the GREEN wires. That is the PS_ON circuit, not
the PWR_GOOD circuit. The PWR_GOOD (PG) wire is typically gray.
 
ric said:
???

You referred to the GREEN wires. That is the PS_ON circuit, not
the PWR_GOOD circuit. The PWR_GOOD (PG) wire is typically gray.
Click to expand...

You're absolutely right. That was a major typo on my part. But those
measurements were for the Power_On signal because I turned on the power
supplies by connecting the ammeter between green and black wires.
 
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