Troubleshooting ASUS A8N-VM CSM

[dcatoni]

My A8N-VM CSM ran almost 24/7 for four years and was the most stable computer I've ever had. Then it started freezing up all the time and shutting down programs. I ran memory tests and processor tests multiple times which showed no errors. I also swapped memory to be sure it wasn't that. I reinstalled Windows which didn't help. I thought for sure it would be bad caps, but I just built the Blue ESR meter and all the caps tested good. Visually everything looks fine on the board, nothing burnt or swollen. What should I do next?

Thanks
Dante
Rhode Island

[mockingbird]

Re: Troubleshooting ASUS A8N-VM CSM

You can't test caps in circuit.

I repaired an A8N, and around the VRM was 8mm UCC KZGs (They are brown caps with a honeycomb type vent). Chances are you have those caps, and if you do, you'll need to replace them with something else. I used Nichicon HM.

If you show us a good picture of your board, someone can tell you what needs to be changed.

[dcatoni]

Re: Troubleshooting ASUS A8N-VM CSM

This image looks better than I could take myself. I was thinking I have to change all the 8mm caps on this board and that it would probably be OK to leave the nine 6mm 100μF caps alone. Is that correct? I really appreciate the help.



Dante

[mockingbird]

Re: Troubleshooting ASUS A8N-VM CSM

You should change every cap on that motherboard. It looks like they're all KZG.

Everything except for the really tiny ones without a vent, that is.

My guess is you have a combination of:
16V 1000uF
6.3V 1500uF
6.3V 820uF
16V 470uF.

All 8mm.

1) https://www.badcaps.net/store/produc...products_id=69
2) https://www.badcaps.net/store/produc...roducts_id=136
3) https://www.badcaps.net/store/produc...products_id=71
4) https://www.badcaps.net/store/produc...products_id=73

[dcatoni]

Re: Troubleshooting ASUS A8N-VM CSM

I just started desoldering. I took out the two next to the processor near the edge of the board, they both tested 0.01

How many should I remove before concluding that the caps might still be good?

[mockingbird]

Re: Troubleshooting ASUS A8N-VM CSM

8mm KZGs:

UG!
------------------------------------------------------
FJ, FL, WGL2, NRSJ -- [.016][.013]
MBZ, HM, WG, GD, KZG, NRSK -- [.018-.019][.013]
KZG, ZLG -- [.020-.021][.013-.014]

I would preemptively recap them even if they are good.

[dcatoni]

Re: Troubleshooting ASUS A8N-VM CSM

I just ordered all 42 caps, but I'll test the board before changing the 100μF ones. These things don't like to come out of the board.

Dante

[retiredcaps]

Re: Troubleshooting ASUS A8N-VM CSM

Did you check your power supply? It may have bad caps inside?

[mockingbird]

Re: Troubleshooting ASUS A8N-VM CSM

I just ordered all 42 caps

I only counted 31 that warrant replacement. You're really wasting your time replacing the small ones, as they're probably a reliable series and you risk lifting the traces whenr eplacing them so the less you meddle, the better.

Did you check your power supply? It may have bad caps inside?

Yes, you most certainly should crack that thing open.

[dcatoni]

Re: Troubleshooting ASUS A8N-VM CSM

I took this board out of service over a year ago. My new one has been running on the same power supply since then, so I'm sure it's fine. I've checked the voltages too, because it makes a high pitched whine. I had the first one replaced under warranty because of this, but the second one has been doing it for 5 years. It's a common problem in the Antec 300.

I want to use this old board for a low budget HTPC build since I have the memory and CPU.

OK, I won't change the 100s. I like to build electronics projects so I'll use them for something. I've just never worked on a mobo before.