ATX PSU failure and diagnostics

Good day all!

I have an ATX power supply for a small form factor PC (Shuttle, I-will XPC) and it is currently broken. Inspecting the power supply, i found out that when I jumper Pin 14 and Pin 15, the fan will spin (indicating that there is power) however it will die out eventually after a few seconds. After working with GOOGLE and searching forums and all, I found out that a certain TTL transistor is responsible for latching the circuit from POWER_OFF to POWER_ON, the problem is, Im not pretty sure if this is the right diagnosis, and if there are other possibilities why this PSU wouldnt power up.

I would really appreciate if anybody can give an insight to this, I would give further details on my troubleshooting if asked. :)

thank you very much

- Mannix

Reply to
happykamote
Loading thread data ...

Hi Den Mon, 26 Sep 2005 20:30:51 -0700. skrev snipped-for-privacy@gmail.com:

That's proberly not the problem, there will be a 100 other reasons. Is folds back for safety reasons, indicating that there is a problem with the output voltages.

My best bet is capacitors, capacitors and capacitor. Replace all electrolytics, except the primary ones (2 fat ones rated 350v or so) and you're back in business. Remember to use 105deg low esr types.

formatting link

An excellent introduction. Read it and understand it.

Best whishes

--
Med venlig hilsen

Christian Treldal
Reply to
Christian Treldal

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.