GMT 4200 Air Precision Electronic Clock

The clock requires two 28 VDC supply. 5 volts required for the backlight.

Electronic Clock Pinouts

Clock Standby Supply Y (28 VDC), <c (ground)
Clock Normal Supply V (28 VDC), D (ground)
INT LT/ANN LT Test J
Integral Light K (5VAC), L (ground)