Faulty Capacitor Replacement

There is a known issue with faulty capacitors causing all sorts of problems. This is pretty well documented here. 

A major cause of the plague of faulty capacitors was industrial espionage in connection with the theft of an electrolyte formula. A researcher is suspected of having taken, when moving from Japan to Taiwan, the secret chemical composition of a new low-resistance, inexpensive, water-containing electrolyte. The researcher subsequently tried to imitate this electrolyte formula in Taiwan, to undersell the pricing of the Japanese manufacturers. However, the secret formula had apparently been copied incompletely, and it lacked important proprietary ingredients which were essential to the long-term stability of the capacitors.[8][9]

Pictured here on the left is a machine that I was working on today. Customer stated it was locking up randomly, sometimes a BSOD, sometimes not. Initial scans showed some viruses and malware, but I suspected a possible thermal shutdown might have been going on. (The fans and inside were filthy with dust)

Many times I have seen machines diagnosed with a faulty motherboard, when in reality just a few caps had gone bad, and caused major instability with the system and can sometimes be a bear to troubleshoot. Once I saw this guy I knew I was going to have to dismantle it all and repair, and check out the state of the CPU/heatsink while in there. Let's see what we found!






Ick, yeah. This is not good. Dust all through the fan, and that compound you see there is what came from the manufacturer. It's a cheap pad, they wear down over a longer period of time. Not exactly that efficient from the beginning, but certainly needs replaced. We'll do that later however. That heatsink is holding down the backboard to the motherboard, I need to get to the rear side in order to desolder the problem capacitor and install a replacement.







Here's the board removed, and me using an awesome desoldering gun.  One of the first things I talked Jose' into purchasing when I came onboard with Interspace. Slightly pricy, but anyone who has had to desolder components from a board knows that it can be painful without the right tools. This bad mamma jamma makes quick work of tough removals. 

Pro Tip: most boards you find today are set with unleaded solder with a wave solder process. This stuff doesn't want to flow like a good lead solder does. When working on these components, I have found a good trick is to keep a roll of leaded solder around. (Pro tip 2, don't chew on it unless you want to end up like me.)  Flow some of that onto your joint with high heat, it mixes with the unleaded and when you hit that with the gun it comes right out.


















This is the CPU after cleaning and applying some proper ceramic thermal grease. I didn't take any pics of the rest of the process, as it's fairly boring. If you decide to attempt a repair yourself, there's a couple of things to make note of:

1) Capacitors have polarity. Check to make sure you align the negative on the cap the same way the rest of them are installed on the board. If you look to the right of the CPU in this last picture, you can see a strip of slots for 6 capacitors, only middle two are utilized. The silk screen on the PCB tells you which is negative and which is positive.

2) When choosing a replacement capacitor, make sure you are matching the correct voltage. The farad rating can be as high or higher than the original cap, just not LOWER.


This is getting less and less common today, as it seems the world might have finally worked through most of the millions of bad capacitors manufactured. It's not always cost effective to do, but depending on the service I will many times do it for free when doing other work, just to ensure stability of the product and to save the customer having to end up buying a motherboard or a whole new PC (it happens).



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