DIYbanter - View Single Post - Kind of a generic electrolytic cap question

Ralph Mowery

In article ,
says...

'lytic caps go bad eventually. After removing the caps for testing you've already run the risk of damaging the board. Why put the old ones back? In broadcast gear small value caps are the most common failures. I've replaced thousands of 100uF 25 V caps. Unit price 32 cents, 1000 for $83. Buy in bulk and replace in bulk. It costs
less than testing and re-installing.

G

Right, at the small cost of the capacitors, it is foolish to put backin
an old one even if the board may have other problems and not used.

Now if it was a $ 10 or even maybe a $ 5 part it may be worth putting
the old part back on.

At the rate capacitors fail, the one that tested good may go bad much
sooner than a new one. Then you have to do it all over again.

It takes often takes more labor time and effort to test than to just put
in a new one.

Like where I work, a man from the factory came in to repair a 480 volt 3
phase 200 HP motor speed control. He found 2 bad dioides that were
rated at something like 200 amps. I asked him to replace the 3 rd one.
He told me those things cost arond $ 200 each. I told him that with 2
bad it may have weakened the 3 rd one. With the machinery costing the
company over $ 1000 per hour for down time, and the cost of getting him
back in the plant, I am willing to pay $ 200 for insurance and piece of
mind. That old diode may pop in a day or 10 years, but I know that I
have done my best to make sure the machine keeps on running for minimal
extra cost.