I've just finished building my APM and have been going through the manual step by step. I seem to have hit an issue with the servo output for the dancing servo test. Ch1-4 are really jittery but 5-8 work fine. I guess it has something to do with the mux chip but dont really know what is going on.
-No servos plugged, in power on (+5v to the pwr pin), everything looks happy, all leds on no flashing
-If I put a servo on ch5, pwr on, the servo sounds good no jitter just dancing! and the mux led flashes slowly, looks to have some relation to the dancing pattern
-move the servo to ch2, pwr on, the servo sounds like its stalled moving jittery only now and again, mux led flickers like crazy (pwr off nice and quick before something goes!)
I did note this in the manual:
"Also note that some of the early boards had the fuses in the Atmega 328 chip (PPM encoder) misprogrammed. If so, your board will not read all channels and will show glitchy servo output. If this is the case, please return it to Sparkfun for reprogramming."
Sounds likely but I really don't want to return the board as I just got it and it would be like giving an xmas presents back to Santa! :(