Bad Capacitors

Capacitors are manufactured by placing a layer of foil over a layer of paper and rolling it around two metal contacts, then sealing it inside a small canister. The paper is soaked in an electrolyte acid. Some company, as its rumored, stole this electrolyte formula from another company and it was either incorrect or incomplete and then resold this formula to capacitor manufactures for a great price. Now many manufactures have used these bad capacitors, from motherboard manufactures, TV, Stereos and are effected with products that fail after 1-3 years because of these faulty capacitors. Motherboard I have seen will do anything from reboot randomly, hard lock at different times, and some fail altogether. It seemed to start in 1999 and I have seen motherboards still using these faulty capacitors today. I have use Asus brand motherboards for about 5 years now and have not seem a problem with them.

Looking for evidence of failure
Failure can be bulging capacitors, gel leaking out of the top, and some have even reported exploded capacitors similar to a little firecracker pop. The best way to test them is with a multi-meter than can check capacitors. Most meters will tell you to desolder from the board so you don’t damage more components.

In this picture some of the caps are bulging and some have gel coming out of the top

Its pretty clear something is wrong with these. They are 2200uF 10V Capacitors, about 9 on are this board. Multi-meter readings for the bulging on came up to 500uF, this is WAY to low. Surprisingly the ones with the gel coming out of the top were far closer to the 2200 mark, they read around 1500uF. Again, this is still to low. And bad caps are not limited to motherboards. Next is a Behringer Mixing Console.

Behringer Eurorack MX 1604A
This mixing console started acting up after about 3 years of continual use. It was left on 24/7 as it was my sound controller for 3 computers. It has a Main out and ALT 3-4 out so I could control all 4 of my speakers and input from 3 computers all on one $100 console.

What started happening is, all the mute lights would flash on and off for all the channels, as well as the peak lights. The main output was putting out large volumes of white noise and static. So I decided to pull it apart for fun, as its hardly worth any money.

54 Knobs, 41 screws, 21 nuts, and 11 fader buttons to pull on this little thing took some time.

I examined the PC board and components and found a little brown burn marks around one of the main capacitors, it looked like it was around the power supply, very close to a couple transistors and a L shaped heat sink. This was my first suspicion.

I started pulling the 2 biggest capacitors and checking them. The 2 near the heat sink were 1000uF 35V. The one closest to the heat sink read 850uF, quite low. The next one in line was 950uF about where it needs to be. I bought a new one at Skycraft Parts and Surplus for about $0.50 and it read 950uF, so I installed and put everything back together. I was surprised to put every screw back in, no parts left over, heheh. And the board has been running for about 48 hours with zero problems!

So if you ever have problems be warned about these bad capacitors out there and its a pretty easy fix. I don’t blame it necessary with this mixing console because it got a lot of abuse and usage, about 26,000 hours worth over that 3+ years! Capacitors seem to undergo a lot of stress as they filter out noise in the current, its my belief that bad power supplies in computers can also lead to premature failure of motherboards. The motherboard has a larger load and stress when your PSU doesn’t provide clean power for it. Check your voltages often and watch them closely for small spikes or drops in power.


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