Discolored capacitors

[BargainBin]

My son called from school last week, and said he PC wasn't booting. He and a friend tried swapping out power supplies to no avail. I had hime drop it off at a friend's, and we went and picked it up today and brought it home. I started troubleshooting 10 minutes ago.

Symptoms:

It does not post.
Harddrive spins and HD light stays on
All fans run (including CPU fan)
On 4 of the 11 main capacitors, I can see brown discoloration on the tops. So I am concerned about the Epox motherboard. Have tried it on two monitors (one known good).

Any other things I should swap out and check?

I will be looking at swapping known good video card while I wait for further instructions.

[BargainBin]

O.K. tried different video card, still no post.

[mrrobotto]

Sounds like its time to go motherboard shopping unless its still under warranty then you can rma it.

It's usually cheaper or as cheap to buy a new motherboard then it is to have to have the capacitors replaced.

[Rocketmech]

You have bad caps , http://www.badcaps.net/ident/ . I've seen in on many makes of boards and psu's , so its not an issue with one in particulair , although Epox has had there share. Replacement or repair is eminent if you want the system to work again. Its possible Epox will repair it if its still within warranty. If your a handy DIY'r , then its easy enough to repair or replace the board yourself ,the latter being the easiest. A local TV repair shop can repair the bad caps , but the cost should be less than a new replacement board. Most people elect to replace the board.

[bubbalou32]

It's also fairly easy to replace them yourself and save money. The caps can be purchased at any electronics source. Some MB manufacturers have extended their warrenty in view of the bad caps fiasco. I replaced the caps on my Soltek with caps that were shipped free from the factory just for asking.

[Ol'Tunzafun]

Bad caps may or may not be the problem at hand, but in any case, the solution will involve pulling the motherboard out of the case, even if only to test it by stripping all components not required to boot, and then adding them back one at a time until the problem rears its head again. If you are going to do all that then you may as well replace the board now because sooner or later it will be necessary and as it is, it has little or no real value. I would recommend replacement because it is a lot quicker and safer.
If you want to tackle repairing the board, then I would encourage you to do so after the board has been replaced and you can work on it at your convenience. It is possible to replace all the caps and then discover that the problem was something else like a blown resistor or IC chip, so success, while likely, is not guaranteed.
When you get the new board, you might want to reassemble it all outside the case on a phone book to confirm that it boots before proceeding with the final assembly.

[RamonGTP]

My EPoX board (8RDA+) blew its caps as well, unfortunatly for me it took the processor along with it. It was pretty much my own fault though, I had it on an underpowered generic PSU and noticed the caps going bad long before any perminen damage was done. It was a system I put together out of spare parts I had collected from upgrades on my main rig, so it wasn't really worth it for me to change any parts out. I pretty much tortured that thing until it died.

[Bovon]

It's also fairly easy to replace them yourself and save money. The caps can be purchased at any electronics source.

General, over the counter types from places like Radio Shack, and even most places that sell to TV shops do not carry these 'special' capacitors. These caps are low equivalent series resistance (ESR) capacitors made especially for circuits (like motherboards) that have high frequency circuits working.

There have been some efforts to repair with every day types with mixed results.

[BargainBin]

Thanks for all the advice. I am pretty sure having looked at the pictures, that the capacitors are bad. I did not know if it was normal for them to go in groups, in this case four went at almost the same time and rate.

This is an older 8KLM2 that it going for $10 on eBay, and may or may not be worth fixing. Is it possible something else has gone wrong and caused the caps to deteriorate (high quality PSU in this unit)?

[fishybawb]

Is it possible something else has gone wrong and caused the caps to deteriorate (high quality PSU in this unit)?

It's possible, but unlikely. If you do some background reading on http://www.badcaps.net/causes/ you'll see that this is a widespread problem in the computer industry, caused by a faulty electrolyte formula

[BargainBin]

As Ramon says, it is possible my CPU has been taken out as well. Any telltale signs I can look for that will provide a clue? The CPU is not that great, so it will probably not sway my decision on the motherboard, but I would like to find a way to test it. Need an AMD Socket A board to do that. I'll ask around and see who might have one.

[Bovon]

There is no reliable way to test your CPU in that motherboard with the bad caps. Some of those caps that are shorted are in the CPU core voltage system...if the CPU is not getting the correct voltage, it will fail...when it fails, their cannot be any boot at all.

Picking up a second hand motherboard to do a simple/cheap repair is not advisable ...the replacement board was built at the same general time and place as the one you now have..so, its capacitors are very questionable.

I buy a lot of stuff from eBay...I get bit often by sellers of questionable integrity ..but there is no way I will buy a motherboard there now.

[BargainBin]

Thanks, Bovon,

Sound advice, and it reminds me of my first go at a PC repair, when I had a fairly nice (at the time) 800 Mhz Athlon sitting on a not-so-nice Colorboard (off-brand). When the motherboard went, I thought I would save the CPU, but learned the hard way they had gone down together. My guess is the motherboard took the CPU with it.

I've had a chance to remove the now faulty Epox, and sure enough, nine of the twelve larger capacitors are either bulging or badly discolored. The nine midsize all look good, as well as the smaller ones. So it has been slowly deteriorating, to the point where my son said the power button would barely flicker at the end when he tried to boot it. The identical symptoms to my first experience. I wonder now if the shorted capacitors slowly killed the CPU in both cases. I'll not choose my next motherboard based on the make and design of the unknown CPU (its just a Duron - less the loss).