Need help on reviving an old mobo

[Smellydeli]

So the story begins with my sis telling me that the computer isn't turning on after being used the night before. Alight no biggie so far. Press the power button, hear the fans spin then nothing.

Opened up the case, checked the connections and everything seems to be in order. Tried to turn the computer on again and all the fans spin up then slow down. BUT the fans twitched to a stop. Unplugged everything from the PSU except for the case fans and they spun normally. Cracked open the PSU and behold, blown caps on the +12v line (and possibly the +5v)!

Alrighty, replaced the blown/bulged caps and the ones for the 5v rail. Put the PSU back together, hooked the necessary components and disappointment ensues. All the fans spin up but slowly twitch to a stop.

Switched/replaced the RAM around but no difference. No visibly damaged caps on the mobo. Plugged in my own PSU and still nothing! There's United Chemicons, some Rubycons, couple of OSTs and Luxcons.

System spec as follows:
AMD Athlon 64 3000+ (Venice 90nm)
MSI K8N Neo2
Geil GLX5123200UP DDR 400 1GB (2X512MB)
Gigabyte ATI Raedon 9550
Antec SmartPower SL350

Could it be when those caps blew, it took out the mobo?

[370forlife]

Re: Need help on reviving an old mobo

Smartpower = Fujiyuu. Did you replace all of them?

[Smellydeli]

Re: Need help on reviving an old mobo

I haven't yet. I did notice that it was littered with Fuhjyyu caps but I wanted to replace the affected ones first to at least see if it would work still and then replace the others.

If my own power supply (Xcilo 600w in use) isn't powering the faulty board, then the Smartpower isn't the main problem anymore.

[ratdude747]

Re: Need help on reviving an old mobo

ost= fails without visible symptoms. msi is a known culprit. search our site for that model. also look at your graphics card... gigabyte is a know offender too...

[Smellydeli]

Re: Need help on reviving an old mobo

The Gigabyte card uses Nichicon caps that appear to be in good condition. There are some surface mount caps that I'm not able to identify.\

I'll try to replace the OSTs then.

Quick question, what would happen if I filled up empty cap slots on a working mobo?

[ratdude747]

Re: Need help on reviving an old mobo

depends.

oh, and good luck on the re-cap!

[Toasty]

Re: Need help on reviving an old mobo

Could be that the VRM (groups nearest the CPU) caps are bad. The failed SL350 is likely to have been passing the ripple to the mobo for awhile and has caused those caps to fail or weaken. Just because they are not visibly blown means nothing without checking them. Since you'll have to check them out of circuit (they're in parallel), you're better off just replacing them.

Does anything in the area around the CPU look overheated or discolored?

There are 8 or 9 caps close by the CPU (Rubys?) and 4 (UCC?) bigger ones back by the peripheral jacks. I'd go after those first.

>>Quick question, what would happen if I filled up empty cap slots on a working mobo?<<

IF in fact they are being used, more caps won't hurt.

Toast

[Smellydeli]

Re: Need help on reviving an old mobo

Nothing looks discolored or burnt around the mosfet area. The 4 big ones and the 8 smaller ones are UCC.

I was wondering if adding caps would help with overclocking. My Asus M2N-SLI Deluxe Vcore is, iirc, -.05v from what I set in the BIOS. The caps around the mosfet area are Panasonic caps and everything else looks like UCC.

[lucky13]

Re: Need help on reviving an old mobo

Smellydeli

You getting sidetracked?

Why don't you post some pix of the MSI K8N Neo2 board so we can see if there is anything you might have missed?

Finally, have you tried clearing the CMOS (and check the CMOS battery too)?

[Toasty]

Re: Need help on reviving an old mobo

If you're going to overclock, then I suggest switching the caps to polymer. Polymers exceed the ripple handling of electrolytics by a factor of between 3 and 5, depending on the brand & series.

Use the forums' Search and look for:

polymer (250 hits)
poly* overclock (8 hits)
polymod (2 hits)

At the bottom, click the "Show Results as" Threads selection.

Lots of good suggestions and information.

Toast

[Smellydeli]

Re: Need help on reviving an old mobo

Already cleared and checked the CMOS battery.

Polymer caps are rather expensive compared to electrolytics. I don't think I'll be getting those as I know that processor can only achieve about 20% OC and its not like I'll be using LN2 to OC it.

My GA-MA790X-UD4P however is filled with polymers

[lucky13]

Re: Need help on reviving an old mobo

Do you have speaker connected to the mobo?

Does it beep if you try to boot w/o any RAM?

[kc8adu]

Re: Need help on reviving an old mobo

Already cleared and checked the CMOS battery.

Polymer caps are rather expensive compared to electrolytics. I don't think I'll be getting those as I know that processor can only achieve about 20% OC and its not like I'll be using LN2 to OC it.

My GA-MA790X-UD4P however is filled with polymers

i dont see any polys there.
these are polys we installed in dell mobo's.
https://www.badcaps.net/forum/showthread.php?t=4969

[Smellydeli]

Re: Need help on reviving an old mobo

There's no sound from the speakers when connected the headers on the mobo when there isn't any RAM.

The ethernet chips do get unusually hot and the northbridge gets warm when the mobo is just plugged in. I'm thinking that the two 25v caps in between the chips went bad.

Those pics are of the K8N Neo2. Now this is the GA-MA790X-UD4P:
http://www.shoppingsquare.com.au/ima...ducts/8044.jpg

I found this when I was removing the caps from the SL350, don't know if it's still okay to use. The cap was glued to the resistor and it seems to have burnt?

[Smellydeli]

Re: Need help on reviving an old mobo

The day before, I was checking the ethernet chips with a multimeter and somehow got it to post and get into BIOS. Disabled (or at least tried to) disabled the ethernet chips. Pressed F10, shutdown but didn't restart. Tried jumping the ethernet chip and through trial and error and got into BIOS again, however it shutdown by itself. After that I have been unable to get the fans spin/twitch by jumping the power switch.

Was fiddling around again today. First was just plugging the 20-pin and 4-pin and just letting it sit. The ethernet chips and northbridge did get warm and but then after leaving it unattended it became cool/cold.

I jumped the green standby line on the 20-pin and the fans started up at full speed and went down as if BIOS was loaded but would eventually stop. Sometimes it would only spin very briefly. During this time there was no video output. As a correction, with the speaker plugged into the speaker header, there is some electrical crackle sound when jumping the 20-pin cable.

Looked around under the 20-pin socket and found this. Hopefully it's just rosin.

[linuxguru]

Re: Need help on reviving an old mobo

Just a guess - when you were probing the Ethernet chip, you somehow tickled the Wake-on-LAN function and it powered up the PSU. It's possible that the normal ATX power-on button circuit is hosed, but WoL somehow still works. If it's shutting down after that, there are other issues in the mobo, which could well be bad caps (at various locations including the VRM output).

[larrymoencurly]

Re: Need help on reviving an old mobo

I did notice that it was littered with Fuhjyyu caps but I wanted to replace the affected ones first to at least see if it would work still and then replace the others.

I had an Antec with one bulging Fuhjyyu, and all the other Fuhjyyus looked fine and showed low ESR. So I replaced just the bulging one, but just one week later, two other Fuhjyyus bulged, and a total of four showed high ESR.