Here's my update version and some notes at the end:

A B C

01 A2K_00 A2K_01 A2K_02

02 A2K_03 A2K_04 A2K_05

03 A2K_06 A2K_07 A2K_08

04 A2K_09 A2K_10 BCD_00

05 BCD_01 BCD_02 BCD_03

06 BCD_10 BCD_11 BCD_12

07 BCD_13 BCD_20 BCD_21

08 BCD_22 BCD_23 BCD_30

09 BCD_31 BCD_32 BCD_33

10 A2K_11 xxxxxxx xxxxxxx

11 -15V -15V -15V

12 -15VX -15Vx -15Vx (IC20 - OP07)

13 +15V +15V +15V

14 +15VX +15Vx +15Vx (IC20 - OP07)

15 GND GND GND

16 GND GND GND

17 +5V +5V +5V

18 +5V +5V +5V

19 xxxxxxx xxxxxxx xxxxxxx

20 xxxxxxx xxxxxxx xxxxxxx

21 xxxxxxx xxxxxxx xxxxxxx

22 xxxxxxx xxxxxxx xxxxxxx

23 xxxxxxx xxxxxxx xxxxxxx

24 xxxxxxx xxxxxxx xxxxxxx

25 xxxxxxx xxxxxxx xxxxxxx

26 xxxxxxx xxxxxxx xxxxxxx

27 xxxxxxx xxxxxxx xxxxxxx

28 xxxxxxx xxxxxxx xxxxxxx

29 xxxxxxx xxxxxxx xxxxxxx

20 xxxxxxx xxxxxxx xxxxxxx

31 xxxxxxx xxxxxxx xxxxxxx

32 GND_12V GND_12V GND_12V

NOTES:

- The LE signal of the BCD inputs is not on the connector, is a NOR output (IC4 74HC32), it could be that the data outputs of the 2K EPROM are used to do some switching.

- Interesting to see how the relays are controled, therr is this beefy ULN Darlington array.

- Is U20 the final amplifier for the output or is special put for the DAC reference voltage ?

Cheers,

DC1MC