On Jul 20, 12:10*pm, Jon Elson wrote:
Robert Macy wrote:
However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed

No, in general, I don't think the run caps are any more failure-prone
than any other part. *I have had exactly ONE run cap blow in 40 years.
I have had a number of other things fail over that time. *Also, if the cap
is not blown open like a grenade, exactly HOW do you check it? *Probably
any time up to a minute before exploding, no test that won't harm it
will detect a unit nearing failure.

Jon

Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.