I had an odd WTF moment on saturday...

1/10 buggy
trinity 10.5 motor
MMP esc, internal BEC bypassed since forever.
frsky TFR4 reciver
bluebird 661 servo
old AMB transponder

20* endbell timing
45* boost, 20k end RPM
15/87 gearing

I've been running this exact setup for a few weeks.


Problem:
Before my race I turned the buggy on, checked the servo, throttled it up. The motor spun up, cogged and everything went dead.

The internal circuitry on the servo are charred remains of silicon. The RX is 100% dead. the AMB works. The esc/motor work fine.

Any ideas?