Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

[bigbadcap]

I was having intermittent freezes on my computer, found some bad caps and then this forum... I have a new-old-stock replacment MOBO on the way (cheaper than recapping for my old MOBO) but unfortunately in the meantime my computer got worse and will now not POST.

I have two obvious bad caps near the CPU and am hoping to temporarily fix them with local parts, i.e. Radio Shack.

They are 3300uf 6.3V... to the best of my (very) limited understanding, it is ok to replace a cap with a higher voltage/capacitance rating.

Radio Shack shows some online at 4700uf and 35V. They are axial leads but again I'm just looking for a quickie kluge to get me by a few days, so I could bend them to fit.

Any thoughts as to whether that would work? Or would I be better off cannibalizing some other old equipment?

Other thoughts on a likely local supplier (I'm in mid-size town, Savannah GA).

Thanks much in advance.

[bigbadcap]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

Here is a link to the Radio Shack cap.

http://www.radioshack.com/product/in...tic+capacitors

[370forlife]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

1. I wouldn't increase it too much
2. Radio shack caps are not Low ESR so they are not good for this situation.

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

>2. Radio shack caps are not Low ESR so they are not good for this situation.

you're saying radio shack has worse esr than his bulging caps?
hehe...i don't think so.

but there are few things worth considering: how much bigger is 35V cap, will it fit?
how long was it waiting in radio shack store, is it ok by now? should be chjecked with esr meter.
what type is the mobo, a bit higher esr of GP cap won't satisfy all designs, esp. some P4 mobos.

and finally perhaps those badcaps already blew the fets on the mobo, so repairing it might be harder in that case.
(it's important not to wait for a mobo to completely die...change caps ASAP)

but overall i would try it, as what's there to lose?
esp. in case he doesn't plan on sending this board for repair to topcat...heh...

[370forlife]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

you're saying radio shack has worse esr than his bulging caps?
hehe...i don't think so.

what type is the mobo, a bit higher esr of GP cap won't satisfy all designs, esp. some P4 mobos.

but overall i would try it, as what's there to lose?
esp. in case he doesn't plan on sending this board for repair to topcat...heh...

With a high esr GP cap he *could* experience less instability, but still have a lot of instability and eventually the same problems. Using a GP cap in a LESR situation can cause it to fail awfully quickly.

In a situation like filtering on a motherboard, you wouldn't want to move so far up in uf either. OK in power supplies, but this isn't a power supply.

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

>With a high esr GP cap he *could* experience less instability, but still have a lot of instability and eventually the same problems. Using a GP cap in a LESR situation can cause it to fail awfully quickly.

what does "awfully quickly" mean in this case?
he already has mobo that failed awfully quickly because of bulging caps.
and i think GP caps probably have lower esr than those that board was workign with past few months.

how much would radioshack caps last is entirely different issue, but he said he needs temorary fix.

oh yeah, i didn't really comment on capacitance value...offcourse he should aim for closest match...as to wether 4700 would make issues on 3300's place, there were some threads here duscussing it....i don't really remember what was the conclusion on how high can one go to be safe...

but (i stress this BUT!) overall i dunno what's the problem of getting good caps in usa fast?
there's priority mail, ups etc., there are good caps.

when i said "i would try it" i guess i was thinking literally myself...as i have no fast way of getting decent caps.
he does, and he should.
offcourse even that doesn't guarantee board will work, as perhaps fets are blown by now, but either way he should swap caps for good ones.

i would put 4700 instead of 3300 in a mobo i care less about, as an experiment.
but not on mobo i intend to use afterwards for longer periods...heh...

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

curiosity:
if this is correct
https://www.badcaps.net/forum/showpo...7&postcount=75

then 4700uF is well within specs(tolerance) for 3300uF...hehe...

wiki mentions 20%
http://en.wikipedia.org/wiki/Electro...or#Capacitance
"Also many electrolytic caps have asymmetric tolerances, typically -20% but with much larger positive tolerance.[citation needed] This eliminates any need to test and grade individual caps."

if we say it's 30%, then it brings 3300 to 4290uF.

[bigbadcap]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

Thanks much for your replies.

As it turns out, I was able to boot this morning. I cranked the case fans to maximum and even cracked the windows open to keep the processor cap temps as low as possible and I was able to get through the day with "only" 5 or 6 freezes.

I wouldn't have risked the damage (mostly worried about my HD) except that I badly needed the use of my machine... kid's science project due tomorrow.

Anyway I was able to straggle through the day and after reading some of the caveats in your posts this morning I am having a new MOBO delivered tomorrow morning. $20 for the board, $40 for the shipping, hah... but, at least I won't have to gut my computer case twice or spend $10 at Radio Shack.

Thanks again.

[Krankshaft]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

I've seen those 35V Ratshack caps they're axial and Dark Blue (can't remember the brand but some no name) the horribly long lead on the top would have to be bent over and would definitely raise the ESR.

Not to mention they are HUGE.

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

>the horribly long lead on the top would have to be bent over and would definitely raise the ESR.

agin(and again, and again): if you have blown crappy cap, then gp cap will bring down the esr(as blown cap has it probably at 5,10 30 or more ohm), and probably within needed specs...
as for saying that slightly longer lead would bring esr up(if that's what you said) uhm....measure that lead's resistance with esr meter...

btw. do something fun with those crappy gp caps: put few in parallel and measure esr...

but overall, his latest explanation seems like cpu overheating because of dust clogged cooler...
caps with slightly elevated esr actually DECREASE esr when heated...they don't really profit from lower temps...(measure esr of badcap while heating it)
but cpu cooler does.

[PCBONEZ]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

Using GP caps when low ESR is called for leaves noise [static] in your power distribution.
Noise in the power distribution can burn out your CPU, Motherboard[chipset], RAM, and corrupt the data that gets stored on your hard drives.
- Is it really worth it?
.

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

yes, gp caps usage attempts are also known to nuke small cities, what more to say...hehe....

again, if you can get low esr caps, use them where low esr caps previosuly were, indeed(all citizens of usa should be able to find decent caps rather easilly..this site's owner has some to sell)....if not, tinker with what you have, because, will you really be crying if putting gp cap doesn't fix your old and crappy mobo that would be a write-off anyway?

[kc8adu]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

i have done some similar things to make something run long enough to finish a critical job.but i always go back and fix it right when the customer can schedule downtime.yes the radioshack part might tip things in the direction of running ok till your parts arrive.but the problem is too many folks say hell with it its running and forget it.bites them again later.
how about recapping the old board and saving it as a spare for the next "oh shit!" moment?

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

>how about recapping the old board and saving it as a spare for the next "oh shit!" moment?

yes, good idea, just like i did with my msi 6337....
benefit of such approach is you get to work on it when you can, for as long as you want, as there's no rush to buy caps at radioshack....so might as well buy good ones at some other place..webshop or so...

[weirdlookinguy]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

The new board will fail the same way the old one did if it has the same caps. Will probably fail sooner (some caps bloat in storage, eg. teapos). You should do a proper recap and never have to deal with it again.

[i4004]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

how do you know he bought new mobo with crappy caps?
i didn't see him saying it's same model as old one.

[weirdlookinguy]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

He said it was NOS, so I assumed it was an exact replacement for the original.

[PCBONEZ]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

NOS means unused -OLD- crap caps.
They won't last as long as the first time around.

.

[hardwareguy]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

It might work for a month..... Ive seen such "emergency" repairs done at school.

Why the guy did it I have no clue.....the Mouser warehouse is just 13 miles from campus!

[Agent24]

Re: Recap emergency -- Replacing 3300uf 6.3 V - Radio Shack ok for kluge fix?

The new board will fail the same way the old one did if it has the same caps. Will probably fail sooner (some caps bloat in storage, eg. teapos). You should do a proper recap and never have to deal with it again.

Exactly. You're much better off recapping the board with high quality capacitors. It might cost more but it will last longer. The old stock one you just bought might have capacitors in almost as bad condition as the one you have now, if it's the same age.