Hi Peter,

Looks like a "suboptimal" power amp design. Electronics should not blow
just because of excessive actuation. I guess with all the regs you
aren't allowed to replace the busted part yourself but have to let the
service folks sell you a refurb or new version plus labor.



That's correct; also I have not been able to find the schematic of the
KFC225 servos anywhere. I have found out that there is no service
manual as such. One could design an exact functional replica easily
enough but frankly I have more pressing things to do


Would be a nice biz opportunity though if the legal side is properly
covered. If this problem is widespread people would be willing to pay a
premium for a servo that doesn't give up. You don't have to design it
yourself.

I remember a muffler maker in Europe who created an exhaust set for a
popular car that wouldn't corrode out in just a few years. It cost a lot
more but still the muffler replacement sales of the car manufacturer
then dropped substantially.

BTW, the clamp ferrite cores I mentioned the other day might still be pretty useful to diagnose an EMI problem. You can't leave them in there during flight but they are really handy to try out things on the ground, running the engine, keying the mike and so on.



Yes, I could try placing some on the wires close to the oil pressure
gauge amplifier; that would not require any paperwork.


The clamp-on versions (just for ground tests) are often available at
Radio Shack. But usually only the large ones that still have the toolbox
type metal drawer shelves. Then when it works you could use real cores
but this often means re-doing at least one connector unless you select a
very large core (they come up to two inches O.D.).

Regards, Joerg

http://www.analogconsultants.com