Antec SP-500 Burned Resistor and Big Bulging Caps

[Jonny Accelerant]

There are several other threads on the Antec SP-xxx series that can be found using the "Search" function, for anyone looking for help on their Antec PSU's (besides this thread).

This PSU was installed in 2006 on a small business server that has been running 24/7 for the last 7 years before the Server would no longer power on. Replaced the Antec and the Server operates normally.

Visual inspection shows 2 things. 1) There's a small resistor that seems to connect the ground & hot of the 120VAC, that is burnt, and one of the large, (what other threads have called) "filter capacitors", is bulging (but not leaking). I assume both of these will need to be replaced. I have an OCZ that I've gone "maximum" on, and have desoldered every single cap and plan on replacing each of them, but on this Antec I'd like to go "minimum" in order be able to compare the difference between "good enough" and "best possible", so if there's any way to avoid replacing any capacitors that do not need immediate replacement, I'd like to do it that way and see how long the repair lasts.

Questions:

What is the purpose of the burnt resistor? Could it alone cause the problem of the Server failing to start on "power on"? (No fans spin, no clicks, no bios beeps, no HD spin, no nothing).
Could the bulging capacitor cause the no-start problem?

If no to both of these, what is the most likely explanation for the problem?

Is the big yellow rectangle next to the burnt resistor a "start" capacitor? Or what?

Thanks in advance, and any help appreciated.

[c_hegge]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

That resistor is there to discharge the yellow X Cap (which is for EMI filtering) to make sure you can't electrocute yourself by touching the pins on the AC receptacle after you unplug the power cable. It has no effect, however, on how the unit functions and is not the cause of your problem. It could be the bad primary caps, but chances are, just about every cap in that PSU has failed. It's very rare than one of these lasts longer than 3 years without bad caps. Do NOT do a minimal repair on it. Give it a complete recap now, or you will have to keep doing it.

Another good idea on these is to put a 2.5K resistor in parallel with the fan control thermistor. The fact that the fans run so slow on these units is a big part of the problem.

[Pentium4]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Yeah, most caps in those fail, even the 1uF ones. These can be a pain to work on too, they're cramped, and the solder side will be pretty messy. Good units though.

[Escort Eagle]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Yellow X Cap looks OK . Use 1M ohms instead of 560K . Your one of the filter capacitor is bulged . You have to change that filter capacitor (changing both capacitor will be better) . There are two resistors value may be 150K or 220K or 330K parallel connected with those filter capacitors . This Filter capacitor bulged due to damage of one of the resistor . You have to check those resistor and replace them also .

By the way - Is there +5VSB present on the PSU ??

[RJARRRPCGP]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Likely a faulty fan controller that caused Kentucky-fried caps!!

(My SmartPower 500 W) (Even when this looks like an earlier revision) had a faulty fan controller it just randomly stopped turning on one of the fans.

[Pentium4]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

This Filter capacitor bulged due to damage of one of the resistor . You have to check those resistor and replace them also .

Ahhh. So this is how SmartPowers find a way to kill Panasonic primaries

[Behemot]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Yeah basically if you loose the ability to balance the caps, one may get higher voltage than 200 V and in time it will fail. If the difference gets too high, it can be pretty fast…

[mockingbird]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Interesting... Antec put Panasonic primaries in the SP-500 but Fuhjyyus in the SP-450 IIRC.

[stj]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

that must be very old, i'v never seen an antec without PFC

[dmill89]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

that must be very old, i'v never seen an antec without PFC

It is, one of the old CWT built Antecs loaded with Fuhjyyus. I think they were discontinued around 2005-2006 when Antec stopped using CWT and an OEM. I'm almost amazed that there are still any of them around that haven't already been re-capped.

[Pentium4]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

I have a Smart Power made by CWT, date code on the transformer is early 2007, still loaded with Fuhjyyu

[c_hegge]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

http://hardwareinsights.com/wp/antec...supply-review/

Antec continues to use CWT as an OEM and use Fuhjyyu caps (or at least Jun Fool branded versions of them) down to this day in the PSUs they bundle with cases.

[Pentium4]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

^ It's lame that they're still using them but I bet they last a lot longer in that PSU, without the 2 transistor 5VSB, and more room for airflow on the secondary side.

[c_hegge]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

True. The fan controller is also far more aggressive on the VPA500P than it was on the SP-500.

[ben7]

Re: Antec SP-500 Burned Resistor and Big Bulging Caps

Ahhh. So this is how SmartPowers find a way to kill Panasonic primaries

If I recall, I think you were the one who had a problem with primary caps failing on a PSU. It was because of an open-circuited resistor (As Escort Eagle said)

I also seem to recall, someone else on here had a similar looking PSU that cooked the panasonic primary capacitors too.