Bad Power Supply?

[Lex Luthor]

I have an Ultra 500w ATX power supply that I've got connected to a Chaintech ATX motherboard.

The power supply has 20-pin (not 24-pin) and 4-pin power connectors.

When the 20-pin connector is plugged in only, I get power to the fans (CPU, Case and PSU), hard drive and DVD. When I also plug in the 4-pin connector, the CPU fan turns (sometimes) for a fraction of a second and then the system gets no power whatsoever, not even the PSU fans turn.

Bad Power Supply or bad Motherboard?

Any way to troubleshoot further before I go out and buy a power supply (the far easier one to replace) to test?

Also, if I get a new power supply, seems as if all have a 20+4-pin connector along with a separate 4-pin connector. Can I just get a 24-pin female to 20-pin male adapter to make it compatible with the newer ATX power supplies?

 

[Zap]

Most (but not all) 24-pin connectors can have the extra 4 pins separated.

Is the PSU an Ultra 500W V-Series from 4 years ago?

My biggest concern with your setup is that your components may be pretty old. That motherboard for sure is old, since Chaintech exited the consumer motherboard business years ago. Old motherboards tend to die from capacitor failure, as do old PSUs. You can check the motherboard capacitors for any that shows signs of leakage (on top or below) or bulging tops (the X pressed into them should make the top slightly concave).

 

[Lex Luthor]

I replaced the PSU, but the identical systems persist. With the 20-pin connector, all of the fans, including the fan on the PSU turns on. As soon as I plug in the 4-pin connector, everything goes completely off.

If it's a motherboard, why would the PSU fan go off?

It's not going to be worth replacing the motherboard, I don't think.

There's nothing I see physically wrong with the motherboard. No leaking/bulging capacitors.

Anything else I can try before I scrap this?

Should I repost in the motherboard support forum?