Hi, my klipsch rw-12d subwoofer only turns on for a second then shuts off. I removed the power supply and began to check the capacitors. I found a 1000uf 160v cap that read about 850uf. I believed that one to be bad. When I ordered a new one from mouser online I checked the new one before I installed it and it only read 860uf. I thought if caps were out of range by 10% or so that they were no good. Did I recieve a bad cap or am I wrong about the 10%. Thanks for any help!!

 

High capacitance electrolytic caps usually have a 20% tolerance. Hence 860μF is within the 20% tolerance for a 1000μF cap.
However, usually I measure the capacitance to be within 20% over the nominal value, not lower.

 

So, your saying the cap can read between 800uf and 1200uf. That said, you read the 20% over the 1000uf. So at what point is the cap thought to be bad? Below 800uf? I just measured the cap thought to be bad and it reads exactly 842uf. That's getting close to the 20% range on the low end. Do you think it's bad or good? Or just change it?

 

Can you check your meter against another one?

 

Can you check your meter against another one?

I checked the other brand new 1000uf capacitor I ordered and that one reads 862uf.