Current as of Nov 1 2025:
Bus A has sawtooth only when DCU1 breaker pushed.
Bus B has sawtooth only when DCU 2 breaker pushed.
Here is failure mode, showing shorter, sawtooth pulses:
Here is non-failed mode, square pulses:
Very infrequently, the sawtooth will be very pronounced.
We have been warned the the pulses must be 3.5v Peak to Peak. Our good pulses show 3.1v, and the runt pulses from the DCU show 2.1v. Some inaccuracy expected because we are using a 6 foot scope probe, off of a bus tap mid string. If we sampled at the terminator, both would be slightly higher?
Here is the original F900 ASCB topology, with Universal pin numbers annotated.
??=====================================
Current as of oct 31, 2025
The frequent un-commanded disengage comes with LAFCS FAIL, and B16: Servo interface monitor fail on the bit codes
Occasional IRU DATA INVALID.
Occasional Disengage ANN data fault
Not sure about this one:
Initial problem.
AP transfers, AP uncommanded disconnect random, only in flight. MTRIM and YD disconnect most of the time.
+++++++++++++++++++++++++++++++++++++++++++++++++
Older printable data:
34-09-01-A.S.C.B WIRING page 1 
34-09-01-A.S.C.B WIRING page 2 
ASCB cropped 3 pages Printable
