This is Why You NEVER Ignore Bad Capacitors!

[Th3_uN1Qu3]

Re: This is Why You NEVER Ignore Bad Capacitors!

A 5.1V zener won't be able to stop the might of a DC power supply when it's angry! It will melt! I've tried it.

Not if it's a 1W zener against a standby supply. It will short and take out the switching transistor.

[lti]

Re: This is Why You NEVER Ignore Bad Capacitors!

Zener diodes usually short when they fail. This either shuts the power supply down or blows it up.

Also, a properly working power supply might supply slightly more than 5.1V. The highest voltage the power supply is allowed to produce is 5.25V.

[tom66]

Re: This is Why You NEVER Ignore Bad Capacitors!

Slap a 5v1 zener across the 5vsb rail to make sure it never ever shorts a motherboard again.

A 5.1V zener won't be able to stop the might of a DC power supply when it's angry! It will melt! I've tried it.

Use a 5.6V zener, a resistor, and SCR, to form a crowbar circuit, which will short the power supply on overvoltage.

OR, use a better power supply.

[Th3_uN1Qu3]

Re: This is Why You NEVER Ignore Bad Capacitors!

Slap a 5v1 zener across the 5vsb rail to make sure it never ever shorts a motherboard again.

[ben7]

Re: This is Why You NEVER Ignore Bad Capacitors!

it was a 250 watt

thats probably it, it came out of an emachines t5026

explains all of the old owner's bsods (he thought he was infected )

all bad caps jamicons (so was the fan, go figure)

what makes it a shame was that it had thick wire, thick sheet metal box, nice, extruded heatsinks, good board material, and the big caps were nippon chemi-cons. a few apples ruined the barrel on this one... a bit too charred for me to recap it...

I got two emachines that were beyond repair cause the "Bestec" brand power supply had a capacitor blow up in the 5v stand-by circuit, making too much voltage go to the motherboard, and SHORT both motherboards out...

they were bestec ATX-250 12E power supplies, and had good chemi-cons on the board EXCEPT for the 5volt-sub. the capacitor, a jamicon, was in a hot spot on the power supply too, next to big heatsink how could you design a power supply like that? unless you want it to fail in the future..

One of them I was able to fix by replacing the problematic jamicon, but the other had some other fault and was just dead...wouldn't turn on. I assume that a power mosfet failure might have happened but who knows...not worth fixing.

-Ben

[cookieCAM]

Re: This is Why You NEVER Ignore Bad Capacitors!

At least This Did Not Happen To My Arcade Games....

[cookieCAM]

Re: This is Why You NEVER Ignore Bad Capacitors!

That Happend To My Video Card........Sadly

[Trinite]

Re: This is Why You NEVER Ignore Bad Capacitors!

I had an Abit AG8-V go out on me. One of the caps blew suddenly and took out the NB. Fortunately, nothing else was taken out. There was some system instability associated with it, but I thought it was just driver issues.

[backtrack]

Re: This is Why You NEVER Ignore Bad Capacitors!

I have received a Macintosh with a psu that had black stuff covering the transformer, capacitors, everything you name it! There was also black stuff on the outside. The voltage rail was toast and perhaps beyond repair. The psu did not stay around for long.

[ratdude747]

Re: This is Why You NEVER Ignore Bad Capacitors!

recap it... my friend has an old soyo (all wendell and sacon) that i am recapping for him right now. my dad had jetway issues and it was all evercon (sacon before the second name change)... before i fully fixed it, it ran fine after a partial recap, however, i was a tard and killed it during the full recap. i wish i had that board undamaged... nice form factor (7 slots, 2 rows of holes deep), VIA chipset for pIII, possibly tualie comaptible, max 1.5gb ram, and lots built in goodies.

[zaphar]

Re: This is Why You NEVER Ignore Bad Capacitors!

I got that beat... I had a cap pop on a Soyo board, they claimed I samaged the board because there were componates missing (they f'ing BURNED OFF!!)

Did they happen to be Sacon caps? My old Soyo motherboard only uses Sacon caps and it never functioned properly out of the box (apg x8 mode). I personally will never buy anything made by them again.

[JuniperSprouts]

Re: This is Why You NEVER Ignore Bad Capacitors!

I hear you. I would not recommend Bestec ever.

[AudioCraZ]

Re: This is Why You NEVER Ignore Bad Capacitors!

Worst cap meltdown I ever saw was from an old cheap mobo when I used to work at PC Club. Had a computer come in that wouldn't post, pulled the panel, and on the side of the board (the side that sits at the bottom, a cap blew, and caught fire. Burnt up the motherboard, taking out the ram, and several of the IDE cables along the way. Was pretty impressive. Witch I took pictures.

[ratdude747]

Re: This is Why You NEVER Ignore Bad Capacitors!

it was a 250 watt

thats probably it, it came out of an emachines t5026

explains all of the old owner's bsods (he thought he was infected )

all bad caps jamicons (so was the fan, go figure)

what makes it a shame was that it had thick wire, thick sheet metal box, nice, extruded heatsinks, good board material, and the big caps were nippon chemi-cons. a few apples ruined the barrel on this one... a bit too charred for me to recap it...

[everell]

Re: This is Why You NEVER Ignore Bad Capacitors!

Is this Bestec the model number ATX-250 12E?

[ratdude747]

Re: This is Why You NEVER Ignore Bad Capacitors!

I have a ps from a friend. its a bestec. inside, i found a cap that had burned itself and everything around it. i see burnt, ried electolyte dripping out of the fried remains. ash all over inside of box.

YIKES!!!!!

[chipper]

Re: This is Why You NEVER Ignore Bad Capacitors!

So much for the stickers for UL Certification on the box. They didn't work. lol
It's really surprising that we have all been fitted with $20 PSU's in the past , while the system was over a grand in total. Not that I am power hungry , but that is obsurd. I'd say the caps on that board were good , what brand were they???

[chipper]

Re: This is Why You NEVER Ignore Bad Capacitors!

When semiconductor thermal protection material gets hot , it looks for something to eat. Like good ribs , the wire was a microwave meal.

[chipper]

Re: This is Why You NEVER Ignore Bad Capacitors!

It really depends on what will be run on old PSU's , 250watt PSU's were installed on PII systems and mobo's , so they aren't for PIII's or P4's at all. If it runs HOT , it's NOT !

[chipper]

Re: This is Why You NEVER Ignore Bad Capacitors!

yeahhhhhhhh, I would say those caps were white on top for a year or more before that happened. Sometimes when the caps are going they might even blow a fuse in the PSU , where it's soldered onto the board.

Once the fuse has been taken out of the PSU , the fixer puts in the wrong rated fuse , and about 2 days later , this happens. All in the name of ignoring and wanting to run the system no matter what.