Advice needed

[Shekou]

I do not speak english on a regular basis so let's keep it simple.

When I start my computer (ACER Aspire T671 AST671-FP820A) the fans are turning but that's all. After trying many things (other PSU, new graphics card, new CR2032 battery on the mobo(It was testing less than 1V)) I finally started looking closely at the caps and I found 3 bulging caps(see picture). When I measure resistance, one is showing around 0,35 ohm while the others are at 0.

Do you think the my problem is the caps and should I test other things before starting to replace them?

This is my mother in law computer so... no need to say it is VERY important...lol

[goodpsusearch]

Re: Advice needed

The bulging caps are KZG. All the KZG on that board need to be replaced. The KZG caps can fail without bulging.

You can't test capacitors without an esr/capacitance meter.

[Shekou]

Re: Advice needed

Before starting to invest my time and money on this, what do you think my chances are that replacing the caps will fix the computer? I mean, when a capacitor fails, is there a good chance that it will damage other parts of the mobo?

Also, these KZG caps are 1000uF 6,3V. I found Nichicon HZ, HM, HN??? Which ones are the right ones?

[goodpsusearch]

Re: Advice needed

The mosfet next to the PCI-e slot seems cooked... Maybe the bulging caps damaged it or more components..

[Shekou]

Re: Advice needed

I had to give it a try but since it was possible to buy a brand new mobo from the internet at around 35$ I needed a cheap and fast way to fix these caps.

Luckily I found a dead graphic card with TMZ caps showing the same uF and V values. I salvaged all the caps (I know it is not recommended but...) and I replaced all 3 bulging capacitors. I didn't even have to remove the mobo from the computer as I had access to the pins from behind.

TADAMM

The computer is working.

Thanks to Badcaps.net

[momaka]

Re: Advice needed

I had to give it a try but since it was possible to buy a brand new mobo from the internet at around 35$ I needed a cheap and fast way to fix these caps.

Luckily I found a dead graphic card with TMZ caps showing the same uF and V values. I salvaged all the caps (I know it is not recommended but...) and I replaced all 3 bulging capacitors. I didn't even have to remove the mobo from the computer as I had access to the pins from behind.

TADAMM

The computer is working.

Thanks to Badcaps.net

Contrats! Great to hear your recap was successfull .

Unfortunately, I do have some inconvenient news for you: those TMZ caps you used are also know to be unreliable, and very likely you will end up with the same problem again.

The fix is to use high-quality capacitors. You are on the right track to use Nichicon HM, HN, or HZ. Any of these will work, but do NOT use old HM/HN/HZ caps pulled from old hardware, especially if they have printing on the side that says H01** to H04** (where ** can be any 2-digit number) - these are problematic too. If you buy from the BCN store here, then you don't have to worry about that.

Also, you should change ALL caps that say KZG on them, especially since you had a few failed ones in your system - that means the others are not far behind.

[Shekou]

Re: Advice needed

Thanks for the info but I think that as long as it works... This computer is mostly for the kids to play with.
I do have another problem though...

This mobo has an old Radeon Xpress 1250 integrated in it so I inserted a better graphic card in the PCIe slot but the computer failed to restart :-( Could this problem be related to bad caps too?

Goodpsusearch was talking about a toasted mosfet near the PCIe slot, I have no idea what a mosfet is doing or if it is linked to the PCIe slot.

[SteveNielsen]

Re: Advice needed

I'm not sure the MOSFET is toasted but it here's a simple go/no-go test which I've used in and out of circuit but out of circuit is preferred:
http://www.utm.edu/staff/leeb/mostest.htm

Attached is pin-out for that MOSFET.

[momaka]

Re: Advice needed

Goodpsusearch was talking about a toasted mosfet near the PCIe slot, I have no idea what a mosfet is doing or if it is linked to the PCIe slot.

If that MOSFET was bad, the motherboard usually won't work at all. It does look toasty/overheated though - probably from working harder than it should due to more bad KZG caps that are bad but just aren't showing it.

-- YES, a cap CAN be bad but still look fine on the outside. That said, if a cap is even at the slightest bulged - it's done for.

So my suggestion is to still replace all of the KZG (and now "new" TMZ) caps, before the problem gets worse and that MOSFET that goodpsusearch mentioned, fails as a result of the bad caps.

I have plenty of hardware that went from a "simple cap problem" to "completely unrepairable" due to bad caps, so if I see them, they go.