Electronics Issue ATX PSU Cap Eruption

[Daves69]

Yep, Capacitor eruption. Antec EA 750.
Bulged the top, smoked, and pissed itself out the intake fan and all over inside. Fortunately it didn't set off the smoke/monoxide alarm. Heard of this previously but never seen it happen till the other day. It is one of three in there.
This PSU might have a whole hour on it but it's out of Warranty. I'd hate to just trash it.

Found caps same physical size and micro farad but with 450 Volt rating.
Any thoughts on replacing the 420 Cap with a 450?

Yea? / Nay?

 

[halifaxhops]

450 should be fine.

 

[black_bishop]

surprising from an Antec, i am on probably six years with the one i'm using atm (knock on wood)

 

[RustyRatRod]

I wanna see the carnage dangit.

 

[Daves69]

surprising from an Antec

There are some pretty "disheartening" comments on the net for these Ltec Caps. (shyneez stuff) Then too, Ltec aren't the only ones with negative comment.

I wanna see the carnage dangit.

Lol, I wish I had a video to play for ya'. Best I can describe, it was like a firework smoke bomb hissing away and pissing out electrolyte with gray smoke and stench. The PSU is mounted in the top of the computer case with Cap pointing downward and the fan at the PSU bottom drawing air up into it and pushing out the rear. Carnage is mainly the top of the cap that bulged. The tin case was a quick wipe down. The fan took the brunt of the leak you can see the blades are still gooed up around the outer edges...…

You can see the small amount of bulge here. That's a penny on top of it for size comparison...….

Got the new one in. Powers up and voltages appear good. No clue what it will do under load yet. Still need to clean the fan up. Stinky goo!

 

[TrailBeast]

There are some pretty "disheartening" comments on the net for these Ltec Caps. (shyneez stuff) Then too, Ltec aren't the only ones with negative comment.



Lol, I wish I had a video to play for ya'. Best I can describe, it was like a firework smoke bomb hissing away and pissing out electrolyte with gray smoke and stench. The PSU is mounted in the top of the computer case with Cap pointing downward and the fan at the PSU bottom drawing air up into it and pushing out the rear. Carnage is mainly the top of the cap that bulged. The tin case was a quick wipe down. The fan took the brunt of the leak you can see the blades are still gooed up around the outer edges...…

View attachment 1715280989

You can see the small amount of bulge here. That's a penny on top of it for size comparison...….

View attachment 1715280996

Got the new one in. Powers up and voltages appear good. No clue what it will do under load yet. Still need to clean the fan up. Stinky goo!

View attachment 1715280990

I have fixed so many supplies and motherboards both with that problem I don't even bother to keep track.
That's why I agreed on the 420 to 450, because I have done it so many times.

 

[Daves69]

I have fixed so many supplies ......

Did you just change the bad one or replace all three in my case?

 

[TrailBeast]

Did you just change the bad one or replace all three in my case?

Never replaced any in your case, but a lot of others.
Sorry, I had to.

I never saw any reason to replace any that didn't show a problem unless I replaced an obvious bad one and still had issue's.
It's pretty rare that they don't show some outer sign of being bad if they are, but it does happen.
Due to their design if they look ok they generally are.
All they are is a strip of metallic material rolled up into a can with insulating substance between the layers.
When they overheat or short they tend to swell and pop like yours did, although not usually quite as dramatically.

 

[67Dart273]

A higher voltage rating on an electrolytic cap is always "good." But I would try to find out what the circuit actually runs for voltage. It might be that the thing is still marginal

In this day and age there is NO EXCUSE for not having good quality caps. Even back when I was young they didn't fail often, and often when did, was because of long storage non-use.

 

[Daves69]

............was because of long storage non-use.

Actually, this PSU has done some shelf time. Probably 3-4 years. Only about an hour run time with it.

...….find out what the circuit actually runs for voltage. It might be that the thing is still marginal

Lol, my electronics knowledge is in the peewee league.
I had the thing jumped and powered up.

Pin outs voltages (if ya' can read my scratch marks) on the 24 pin are...…………..

 

[67Dart273]

LOL no I meant whatever is actually applied to the cap

I've seen "all kinds." In amateur radio, the old school linear amplifiers (legal in amateur work, we get to run up to 1500W out the chute) some amps had VERY marginal capacitor strings.

I had the remains of an old Swan I think it was a "Mark II" This had electrolytics wired in series for the tube anode, about 2700V there were 8 caps at 400V each, so you only had a working rating there of 4x8= 3200V. Not much headroom

Photo like it I stole off the www

I rebuilt the power supply with a larger transformer I had (old one was bad) and replaced all the caps with one big "medical cap" 35 ufd at 5000V.

Sometimes, you can (stupidly) push ratings "over the top." Years ago I traded for a Heathkit SB-220 amp, and the power supply caps were gone. I was in a hurry to get it on the air so late one Sat nite I found a couple of oil-filled WWII surplus caps I had. They needed to be matched, but I either could not read the ratings or MIS read them. I ran them for several months. Later I tore it apart to install new ones, and discovered that the some odd 2500--3000V B+ was across TWO 600VOLT CAPS for total of only 1200 VOLTS!!!! Bear in mind these were "conservatively rated, built like a battleship" WWII military stuff, and were oil caps, not electrolytics

www photo of a Heath SB-220: The caps mount in the "Danger High Voltage" box

 

[Daves69]

Lol, Del!!
By what you're saying, (I'm "assuming"), applied voltage could be exceeding the cap(s) rating causing the fail. And it may happen again.
But you're way over my head for testing the circuit.
I'm like...……….


I think I'll fire it up with an old MB after this global warming weather passes and I can get outside with it. Don't want it puking again inside! Maybe I can get RRR a video!