CHIEFTEC CFT-56--A12S Dead Short

[a1guitarman]

I replaced the large 470uf 450v cap in said above PSU. I'm just learning and I might add the hard way most of the time. Anyway, I saw the original cap bulged on top, pulled it and found it bad. I should have checked the darn fuse too... but didn't until the new cap was in and still no start. Sooooooo.. now I don't know how to check for a short or even where to begin. Thought I'd start here on BadCaps for some advice before I toss my 7 dollar cap in the trash.

Thanks..

[a1guitarman]

Re: CHIEFTEC CFT-56--A12S Dead Short

Some photos.

[c_hegge]

Re: CHIEFTEC CFT-56--A12S Dead Short

Check between the pins on the PFC and switching transistors with the resistance or Diode check setting on your DMM. If you get 0 between any of the pins, your transistor is shorted.

[ben7]

Re: CHIEFTEC CFT-56--A12S Dead Short

The bad filter cap might have caused the PFC circuit to go bonkers. Check the PFC MOSFET, diode, and also check the main bridge rectifier.

[a1guitarman]

Re: CHIEFTEC CFT-56--A12S Dead Short

Hi..

Thanks for getting back to me !! Being a newb.. could you folks please point out where these components my be? I know what a mosfet is, but not sure where the transistor and diode is you wish me to check.. I'll be happy to post other photos if you like.

Thanks sooo much..

[c_hegge]

Re: CHIEFTEC CFT-56--A12S Dead Short

They'd be attached to the primary heat sink (the one with the big cap next to it).

[a1guitarman]

Re: CHIEFTEC CFT-56--A12S Dead Short

Thanks C Hegge..

Been really busy but will check it out when I come up for air. I'll post my findings :>)

[a1guitarman]

Re: CHIEFTEC CFT-56--A12S Dead Short

I gave up :>(

[c_hegge]

Re: CHIEFTEC CFT-56--A12S Dead Short

Sad to hear. It looks like a decent PSU, probably worth reviving.