Avionics Bending: Flap Position Indicator (Pinout)

The flap position indicator is actually a quite sophisticated instrument. Fully synchro driven it not only requires synchro input signals, but it also acts as the 26V 400Hz source for what would have been the synchro transmitters attached to the trailing edge flaps (see right hand side of the larger schematic).

The image above shows the Flap Position Indicator powered off but with back illumination on. In this state the tapes roll about half way down the instrument to the "OFF" indicators. The two tapes are really independent from each other and only share a few common logic pieces. All of the motors and position synchros are unique to each tape. 

Below is the full schematic for the L-1011 flap position indicator:

The complete pinout for the L-1011 Flap Position Indicator:

Connector	Pin	Function
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P1	01	Chassis Ground
P1	02	115V 400HZ AC Power Lo
P1	03	LE TRANS Annunciator Lo (5V)
P1	04	Instrument Ground
P1	06	26V 400Hz Output
P1	07	5V Instrument Lighting Hi
P1	08	5V Instrument Lighting Lo
P1	10	Left Flap Tape Synchro Input X
P1	11	Right Tape Synchro Input X
P1	12	LE TRANS Annunciator Lo (5V)
P1	14	LE EXT Annunciator Lo (5V)
P1	15	LE EXT Annunciator Hi (5V)
P1	16	115V 400Hz AC Power Hi
P1	17	26V 400Hz Signal Ground
P1	21	Left Tape Synchro Input Y
P1	22	Left Tape Synchro Input Z
P1	23	Right Tape Synchro Input Z
P1	24	Right Tape Synchro Input Y