I've been trying to test a few mini itx power supply units (PW-200M) which I've accumulated and which have 20 pin ATX connectors.
More info here.
200 Watt DC-DC ATX
and photo below
https://www.diyaudio.com/forums/attachment.php?attachmentid=905865&stc=1&d=1609255652
Originally I tried the "paper clip" test shorting out the "power on" pin 14 to ground - I used the adjacent pin 15 - with a paper clip. Then I connected up a 12 volt power supply to the feed in, and then checked for voltages at the 12 and 5 volt pins - nothing!
Next stage, after further Googling, I found an article suggesting that as well as shorting out pin 14 and 15, I needed to add load, the suggestion was to use a 5W 10 ohm resistor to add load. I bought a resistor and connected it across pins 3 and 4 and again connected up to my 12volt bench supply . Again nothing!
This was the same with all 3 PW-200M's I tried. Thinking it odd that all 3 could be faulty, I connected one of the power supplies to a mini ITX motherboard, applied 12 volts to it and the motherboard fan spun into action and I could detect voltages from the various power supply leads. This was the same with both the other 2 power supply units.
Now I know I could have saved myself all the hassle by just using the motherboard test in the first place, but initially the paper clip test seemed so simple.
Just curious as to why the paper clip test doesn't work. Anyone any ideas?
PS I've checked the voltages across the various pins of the ATX connector when it's powered up to the motherboard and the output voltages all correspond to ones expected from a 20 pin ATX connector ,so I don't think it's a non standard design.
Thanks
Alchad
More info here.
200 Watt DC-DC ATX
and photo below
https://www.diyaudio.com/forums/attachment.php?attachmentid=905865&stc=1&d=1609255652
Originally I tried the "paper clip" test shorting out the "power on" pin 14 to ground - I used the adjacent pin 15 - with a paper clip. Then I connected up a 12 volt power supply to the feed in, and then checked for voltages at the 12 and 5 volt pins - nothing!
Next stage, after further Googling, I found an article suggesting that as well as shorting out pin 14 and 15, I needed to add load, the suggestion was to use a 5W 10 ohm resistor to add load. I bought a resistor and connected it across pins 3 and 4 and again connected up to my 12volt bench supply . Again nothing!
This was the same with all 3 PW-200M's I tried. Thinking it odd that all 3 could be faulty, I connected one of the power supplies to a mini ITX motherboard, applied 12 volts to it and the motherboard fan spun into action and I could detect voltages from the various power supply leads. This was the same with both the other 2 power supply units.
Now I know I could have saved myself all the hassle by just using the motherboard test in the first place, but initially the paper clip test seemed so simple.
Just curious as to why the paper clip test doesn't work. Anyone any ideas?
PS I've checked the voltages across the various pins of the ATX connector when it's powered up to the motherboard and the output voltages all correspond to ones expected from a 20 pin ATX connector ,so I don't think it's a non standard design.
Thanks
Alchad
Attachments
Apply a dummy load to it (like an old hard disc) and see. Most of the older supplies wanted some loading on the 5V or 3V3 lines to turn on.
ATX PSU stand alone, starts with
Green wire ( PS-ON ) shorted to black wire ( GND ).
Green wire ( PS-ON ) shorted to black wire ( GND ).
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Thanks for the replies - but did you not read my post??
Kodabmx... "Next stage, after further Googling, I found an article suggesting that as well as shorting out pin 14 and 15, I needed to add load, the suggestion was to use a 5W 10 ohm resistor to add load. I bought a resistor and connected it across pins 3 and 4 and again connected up to my 12volt bench supply . Again nothing!"
Mchambin... "Originally I tried the "paper clip" test shorting out the "power on" pin 14 to ground - I used the adjacent pin 15 - with a paper clip."
Kodabmx... "Next stage, after further Googling, I found an article suggesting that as well as shorting out pin 14 and 15, I needed to add load, the suggestion was to use a 5W 10 ohm resistor to add load. I bought a resistor and connected it across pins 3 and 4 and again connected up to my 12volt bench supply . Again nothing!"
Mchambin... "Originally I tried the "paper clip" test shorting out the "power on" pin 14 to ground - I used the adjacent pin 15 - with a paper clip."
Just tried connecting an old hard drive - nothing. Then with the hard drive still connected to the power supply, I just connected to my mini ITX motherboard, switched it on and motherboard fan spun and I could hear the hard drive spinning up! VERY weird.
Also, forgot to mention, I have one of these "power supply tester" devices
https://www.amazon.co.uk/YBLNTEK-Co...2&sprefix=power+siupply+tester,aps,215&sr=8-3
I've tested it with some ordinary PC power supplies, both 24 pin and 20 pin ATX versions and it indicates all OK, with the PWM's I get absolutely nothing.
Alchad
Also, forgot to mention, I have one of these "power supply tester" devices
https://www.amazon.co.uk/YBLNTEK-Co...2&sprefix=power+siupply+tester,aps,215&sr=8-3
I've tested it with some ordinary PC power supplies, both 24 pin and 20 pin ATX versions and it indicates all OK, with the PWM's I get absolutely nothing.
Alchad