Bad caps replaced, but how to start the PSU?

[LinPack]

Hi all

My cheap, "generic" PSU suddenly died, so i replaced it with a new one and take the dead one to do some experiments.

First, i opened the cover and found it filled with bad caps, so i replaced them all.

Plug the power cord on, nothing happened

Then i decided to check all the transistors and rectifier diodes: They're in good condition.

I stuck here for 2 weeks, then finally i thought that maybe the PSU need some power to kick off.

Immediately i grabbed my bench supply and bump 12volt into the yellow wire of the dead one.

It works


But now i still cannot figure out how to start it independently. I cannt find the start-up resistor, there's no high ohmic resistor between the 340Volt and the control circuit, just a opto-coupling


Please, explain me more about methods to start a switching PSU.

Thanks alot.

[elbrute]

Re: Bad caps replaced, but how to start the PSU?

Is it an ATX type?
If so you need to jumper the green power-on wire to a ground.

[yanz]

Re: Bad caps replaced, but how to start the PSU?

Yes, exactly like what elbrute said.


example:









See also:

Your PSU is "LIVE", but not "On" :
http://www.jonnyguru.com/atx/index.html


---

Well, the psu will really be dead if it has no +5v on its purple (+5v standby) wire. Measure it on the atx connector with your multimeter.

Please be careful not to touch the inner side of psu when it gets live connection to the main plug.