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Old Nov 02, 2012, 06:18 PM
PeterVRC is offline
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Australia, VIC, Melbourne
Joined Nov 2006
13,926 Posts
Electronically this does not make sense.....

"CC BEC will not work with some of these Chinese servos"

A BEC (or battery even) is purely a voltage source. No 'timing', signal, digital/analogue etc etc involved at all. No type of servo should ever matter at all... except one that requires more current than the BEC can supply wiothout shutting down or frying! LOL

You already said the ESC BEC didn't work either, before the CC was tried.
This is the big clue.....
Something died during your TV setting up... probably a TV servo.... and that killed the ESC BEC, due to shorting or something. You would expect smoke, but is not a definite need to occur when something electronic 'dies', or is 'killed'. eg if it died 'quickly', before major current surge - which is what really fries things into smoke(!) - then you will not see any smoke, but it is still dead.

Then you plugged the CC BEC into a faulty circuit (servo failed possibility).... and in this case, the 'luck' of what unfolded was high current, frying, and thus sparks and/or smoke.

What to do......
Use a BATTERY to test the servos one by one. Watch the RX, or a servo tester, for power drop/cut (LED's going off, or fainter) and IMMEDIATELY disconnect if that occurs.
A battery won't fry like a BEC/ESC-BEC can.
The RX will not fry, because the issue is a short circuit from +ve to -Ve, not the signal line - and the pos and neg power only go to a rail on the RX connector and then out to the servos, so the path of the short circuit just goes into a RX pin, and then out another = not INTO the RX.
PS A "short circuit" does not necessairly mean a straight connection from pos to neg. "Short" means a circuit that takes a shorter PATH than it should if things are working normal. eg in a servo, if the drive transistor of the motor has some issue and IT shorts out, the circuit is still not straight pos to neg, it is just 'one component less' resistance down that path, and thus higher (possibly much higher) current and then a failure.
LOL, too many possible combinations to explain all in detail.... or how electronics all fully work.
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