ANOTHER Antec sp350P with pfc request

[Dabbler]

Hi, I'm a keen amateur repairer of electronics, mainly as a hobby since the time I spend certainly wouldn't feed the kids if I was charging. I'm hoping someone out there can help me. I will try to upload pics, the issue is with a burnt resistor where I don't know its value. (R11)
The 'patient' is an Antec SP350p with PFC PSU with bad caps, but which hardly looks used and is very clean. Since it's a hobby, I put more emphasis on getting it fixed as a spare rather than spending a small fortune re-capping and modding, which is above my level anyway. I include a pic of other area, caps look ok?
Anyway, I removed two swollen caps (EC10 & EC11) from what I understand is the 5v live rail (2200uF and 1000uF, both 10v). The pics are with these removed and to the left is a resistor (R11) that's burnt black and has peeled, so no colour code (that's how we spell 'colour' here!)
I notice in others' pics this position is left empty. I'm not knowledgeable enough to know whether these will be different because of the mains voltage, 230v, but I'd expect that was taken care of at the primary stage?
Anyone out there with the same device or a drawing that would take a look and let me know? I'd also like an opinion of whether this might have caused damage to other components in the supply or computer, or is there a fail-safe built in? I'm not sure what the 4 pin chip is from the left of the caps (as pic) – regulator? (Marked L0625 – 817CN). I think the DVD writer is faulty but I can't power up 'til I have a power supply.......I might just fit the caps and a low value resistor and fire it up (I hope not literally!), I hear others have got away with this repair.
Thanks in advance, apologies if I'm in the wrong place and for any other serious infringements of etiquette I've probably made, (first post!)
Alan
PS there's also a small defect on the board below the burnout I can fix with solder.

[ratdude747]

Re: ANOTHER Antec sp350P with pfc request

Moved from FAQ.

[Khron]

Re: ANOTHER Antec sp350P with pfc request

A couple years ago, i "revived" my Antec SP500P, and if i'm not mistaken, they're basically nearly identical, apart from some component ratings.

I went through my thread, and i think on page 3 or 4, i mentioned i replaced that toasted resistor with a 22ohm one, since it was "on the way" to the Vcc input of the PFC controller chip. You might wanna double-check on the solder-side of the board, though...

[everell]

Re: ANOTHER Antec sp350P with pfc request

A couple years ago, i "revived" my Antec SP500P, and if i'm not mistaken, they're basically nearly identical, apart from some component ratings.

I went through my thread, and i think on page 3 or 4, i mentioned i replaced that toasted resistor with a 22ohm one, since it was "on the way" to the Vcc input of the PFC controller chip. You might wanna double-check on the solder-side of the board, though...

Khron666 - did you get your 5vsb fixed? After much experimentation I found that the Viper 22A was a much better choice of chip to use than the DM311. I have since modified a couple of Antecs with the Viper.....the 5vsb will now load properly up to 2 amps whereas before it would only do 1 amp and shut down. This was due to the transformer feedback windings.

[Khron]

Re: ANOTHER Antec sp350P with pfc request

Hey everell,

Yeah, actually i DID get the 5vsb up and running again. Not sure what was wrong though, but i re-melted all the solder joints, powered it up, and it worked

Glad to see my "patchwork" helped others, especially you Don't forget, one less wire for the mod-board, as well

[Dabbler]

Re: ANOTHER Antec sp350P with pfc request

Khron666, guys thanks for responses, proves I need to work on my site search skills as well as diagnostic, I DID search for ages but didn't come up with this one.

I'll read with alacrity (I had to look that one up) and have a go then post back.
CHEERS!

[Dabbler]

Re: ANOTHER Antec sp350P with pfc request

Hi again, I spent ages on a response then lost it. The gist was that on reading Khron666 posts my approach is cowboy - are there basic easy checks I could make before plugging in to enhance success? I'm learning loads from this thread. Thanks again.

[Khron]

Re: ANOTHER Antec sp350P with pfc request

Well, the first thing you'll wanna do, is do a full re-cap. Get rid of all those Fuhjyyu caps, which are BOUND to fail, sooner rather than later. As far as i know, you can get replacements even from the Badcaps net-store. You'll "have to" go for a lower value for the 12v rail caps, 'cause only(?) Fuhjyyu makes such large values in such small can diameters (and i've got a hunch the ratings might be semi-bogus anyway).

After that, if the 5vsb circuit is still alive (which is sorta doubtful), then you should be getting around 5v between the purple wire and ground (black). If not, it's time for an "everell mod", or that mini-board you can see in my thread, and there might be a link to everell's thread as well (do a search for threads he has started, you should find some Antec "revivals"). If you need more detailed instructions, just ask.

You'll wanna unsolder the primary heatsink and test all the transistors, especially to see if the PFC fet is still ok.

After 5vsb's alive / back, and stable, take out that toasted resistor. That should disable the active PFC.

Make sure you use a "bulb tester", ie. a 60-100w "classic" lightbulb, in series with the AC input. The bulb should flash just once, when you plug the AC in, while the main filter caps charge up. Then, you can try turning on the psu (a jumper-wire between green and black, on the main ATX connector). Since there's no load, the bulb should stay off.

If all is well, and output voltages are ok and within spec, solder a 22ohm resistor where the toasted one used to be. With the bulb tester in place, upon power-up, the bulb WILL turn on quite bright, 'cause the PFC *DOES* suck quite a bit of current, 'cause it's boosting the rectified AC (~320v DC, since i see you're in the UK) up to about 390v DC. If the PFC fet tested ok previously, you can skip the bulb tester and hook up the AC directly. While it's powered up, you should be getting close to 390v DC across the big main filter caps.

I know i might've left some stuff out, but i've had a rotten night's sleep, so, with due apologies, i can't really be bothered to be any more detailed right now... >_<

[Dabbler]

Re: ANOTHER Antec sp350P with pfc request

Much appreciated again, thought I'd have had a go by now but stuff's getting in the way - I WILL let you know the outcome.
First impressions are that some of these may be a step too far for my level, but the tail's still up! I'll go through as much as I can & report back as soon as I get to it.
Regards.