PCA Forums

A friend brought by his computer. He said he came back from a trip, turned it on and it won't POST but fans spin up.

Found that one of the two big capacitors next to the CPU bad popped (blew the cover right off of it).

As an electronic tech I know the only reason for that is a caop that spontaneously failed or else a dead short elsewhere in the circuit.

I've seen a fair number of posts here concerning popped caps on Athlon mobos. Just wondering what else to worry about. I'm assuming the mobo is a write-off, but should I be concerned that something else caused this like the CPU?

Power supply seems to be okay - I'm getting +5 and +12vdc but haven't checked the other voltages yet.

I've seen a fair number of posts here concerning popped caps on Athlon mobos.

Please don't generalize like that. AFAIK The problem is epidemic with the Abit KA7 only, and it's due to excessive ripple current through those particular caps.

The only time I've seen a cap actually POP is with reverse polarity or extreme overvoltage. Otherwise they just vent and spew. I'd almost say the power supply spiked, killing the cap, or one of the Vregs failed, which could overvolt the cap esp. if the mobo takes Vcore or Vio from the +12 rail.

I doubt the CPU actually caused the failure, though it's quite possible it didn't survive. A dead short later in the circuit (after the capacitor) will only discharge the cap, and possibly burn traces due to over current.

Hi Jim,

Didn't mean to over generalize. You all know I'm not an Athlon user, so I don't really pay much attention to posts about them, but I do remember seeing a few here that mentioned capacitors popping - never noticed what mobo it was.

So bottom line: Should I tell him to feel comfortable with just swapping out the mobo, or should I recommend a new power supply?

power supplies are relatively cheap. I'd feel better by recommedind it be replaced.

If you replace the PSU, you may want to go with an Enlight 340W. Drop dead quiet and relatively inexpensive. They're approved right to the top of the heap of Athlon XP's.

This PSU is coming up with 5.19 volts under load which seems high to me, so in the trash it goes. Better safe than sorry.

Curiously the cap that blew was one of the two big ones on the 5 volt bus.