A-power

[ratdude747]

has anyone had "pregnant" caps in an A-power Power supply?

I just had an antec kill am sweet AMD Athlon xp thorton when I decided to chek my other computers, and found a bloated dude on an A-Power 500 watt

i am saddened by this loss- ionly paid 5 bucks for it a few years back (if u are from the US, u'd love Gooodwill stores because of this) and I didnt know about bad caps then, but i sure it was fine then, and dead now

Also, what brands of power supply are good? I want to get a good one this time.

[kc8adu]

Re: A-power

a power are junk.
sledgehammer it and toss.
recap the antec.

[PCBONEZ]

Re: A-power

Vote 2 for the sledge.

[momaka]

Re: A-power

It's tempting to sledgehammer and throw away those piece of crap PSUs. I have to say, though, the PSU will only do more damage that way - especially if you toss it in the trash where the PSU will release who knows how many bad chemicals in the groundwater (you never know what a cheap chinese factory uses to make those things).

Get yourself a nice power supply and be done with the problem. 250-300w Sparkle is perfect for older 5v based systems. FSP, Delta, and Corsair are also some excelent choices for newer systems.
As for the old PSU - cut the wires from the plug to the PCB and give it to someone who can use it (or you keep it) for parts - not that there are many, but still. My favorite stuff are the screws and the fans (which can be used as a load for PSU testing, or as case fans, provided that you put oil in them before using).

[PCBONEZ]

Re: A-power

The only problem with that plan is that aluminum electrolytic caps are not currently recycled as far as I know.

[momaka]

Re: A-power

That ^ and they stink when they've vented .

[ratdude747]

Re: A-power

i also just discovered another antec 300 with 3 bad ones

i hate theese things

I also discovered a lot of my stuff has bad caps but i am only 16- i can't afford recap all of them - most of them still work fine no prob

about the one psu- the fans were also dying o its only good for wres and laughs

[ratdude747]

Re: A-power

oh also, do i need to somehow discharge the ps before opening

[momaka]

Re: A-power

If the PSU has been plugged in to a motherboard and then turned off, it's very likely that you won't need to discharge anything. Most PSUs also discharge automatically. Nonetheless, advise some caution when opening the PSU and avoid touching the primary heatsink. If you have a DMM, set it on DC and measure the voltage on the primary capacitors by attaching one probe to the negative lead and one probe on the positive lead on the output side of the bridge rectifier. If you get 0 VDC, it should be safe.

[PCBONEZ]

Re: A-power

Yes.
-Should- discharge by itself...
Something would have to be broken for it not to.
The two big caps on AC side should discharge through the rectifier diodes or the resistors on the other side of them. Only way they won't is if both resistors and diodes are open, which is possible but isn't too likely.
-
If you wanna cover your butt for 'in case' discharge the caps with a shorting bar.
- aka: a big-ass screw driver.

[Wizard]

Re: A-power

PCBONEZ, that's dangerous assumpation that mains cap discharges through the rectifier diodes. I had many units hold charge for DAYS till one go POW when I accidently let desoldering wick fall across that. Ugggh!

Now I routinely make sure that *da-n* cap is *discharged*! Some are nice to have high resistance resistor across that cap to discharge themselves but this can fail.

Do not ever discharge big capacitor with jumper or tool across it. This high amp and that loud *snap!* is stressing the cap and can blow holes in the capacitor foil and blowing out nicks off tools, no thanks. Use 100K ohm resistor and jumper clip wire, just one hand. This will discharge within few seconds and not so drastic. To be safe after discharging, put jumper wire across that to keep it discharged. They "recharge" to few voltage after a time due to electrons mirgation.

Cheers, Wizard

[Oklahoma Wolf]

Re: A-power

Know what's fun? Discharging a flash capacitor in a digital camera with your thumb because you were in too much a hurry to do it properly.

Hey, why is the camera lying over by the wall now? I don't remember putting it there...

[ratdude747]

Re: A-power

thanks

[PCBONEZ]

Re: A-power

PCBONEZ, that's dangerous assumpation that mains cap discharges through the rectifier diodes. I had many units hold charge for DAYS till one go POW when I accidently let desoldering wick fall across that. Ugggh!

Now I routinely make sure that *da-n* cap is *discharged*! Some are nice to have high resistance resistor across that cap to discharge themselves but this can fail.

Do not ever discharge big capacitor with jumper or tool across it. This high amp and that loud *snap!* is stressing the cap and can blow holes in the capacitor foil and blowing out nicks off tools, no thanks. Use 100K ohm resistor and jumper clip wire, just one hand. This will discharge within few seconds and not so drastic. To be safe after discharging, put jumper wire across that to keep it discharged. They "recharge" to few voltage after a time due to electrons mirgation.

Cheers, Wizard

Like I said:
-> Something would have to be broken for it not to.

If the PSU is working, but not good...
Then you know the rectifier diodes are working.

Using a shorting bar is the proper method.
They have a resistor built in.
Most techs are too cheap to actually buy a proper shorting bar and an insulated screwdriver works just fine for small caps.
-
You are right on big caps. - Should use a current limiting resistor.

Here's an easy way.
.

[momaka]

Re: A-power

If you use a DMM to measure the voltage on the cap[s], they should discharge this way as well.

Know what's fun? Discharging a flash capacitor in a digital camera with your thumb because you were in too much a hurry to do it properly.

When I was in 8th grade, some kid had a disposable camera opened up. He said, "put your finger here". I knew he was getting at something stupid, just didn't know what exatly. Surprisingly, it didn't hurt that much. All I remeber was a stinging/numbing feeling on my thumb. Perhaps it was a weak camera. A PSU capacitor will pack much more ouchies.
--------
I have a couple of 200v crap caps from a few PSUs. I'm thinking about building a coil gun. Would it ruin the caps if I just shorted them straight to the wires leading to the coil (not that the caps are anything special, but still)?

[ratdude747]

Re: A-power

the psu's were "fine"

i just happened to look through a vent and saw the porky cap

so i should be fine to open them up to see what's salvageable inside

btw is the a-power worth doing a full recap on?

[i4004]

Re: A-power

>If you use a DMM to measure the voltage on the cap[s], they should discharge this way as well.

+ for the dmm usage(ie first check if that cap still has charge...if it doesn't then you're safe) but - on the expecting that dmm will discharge it, as voltage measuring typically bleeds very lil current.....

>btw is the a-power worth doing a full recap on?

have you read the 1st reply in this thread?

[PCBONEZ]

Re: A-power

>> is the a-power worth doing a full recap on? <<

It's worth it's value in screws, wire, and plugs.
The rest should go in 'the bin'.

[momaka]

Re: A-power

btw is the a-power worth doing a full recap on?

Most likely not.
----
My criteria for deciding weather or not a PSU is worth a recap:
-PSU has marking "35" on main traffo (most cheap PSUs have a "33" transformer, which is much smaller)
-has decent (thick) heatsinks and decent components attached to the heatsinks - that means absolutely no 2-diode treatment allowed
-18awg wire throughout output side (except floppy connectors, of course).
-As for primary side, wires must be rated for 600v. 20awg is okay for older units powering a PII/P3 or AMD equivalent, but 18awg is much better.
-has proper bridge rectifier, X/Y caps, and a choke coil or 2 (MOVs are also recommended)
----
Post a few pics of your PSU and we will tell you. If it's not worth the recap, it sure will be worth the laughs .

[ratdude747]

Re: A-power

good call
i opened it up
found 5 severely vented caps

at least 1 of the 2 fans was still good