A4 X1 Coder

End is Labeled:

A-4         X1    CODER                            100-101116
N             L              J         H          F            D  C  B   A
G             R             R         R          R           T   T   T  T
r               e              e          e           e            P   P   P  P
n              d              d          d          d


The X1A code is a shift register with the following equation:
1 + X6 + X8 + X11 + X12

The X1B code is a shift register with the following equation:
1 + X1 + X2 + X5 + X8 + X9 + X10 + X11 + X12

Where the exponents are the tap locations that are combined in an or gate and fed back to the input.

The X1 code is formed by the MOD 2 combination of X1A and X1B (i.e. a Gold Code).

I would expect to find a couple of 12 bit shift registers on this board with each bit's output brought out to a pin and some big OR gates and an external or gate to sum the codes.

blank N74LS175B AM25LS163PC electro cap
AM25LS194APC 74128N header   r-----r- SN74LS86N
AM25LS194APC F 93S47PC DM74LS32N TI SN74LS123N
AM25LS194APC 93S48 PC TI SN74LS37N header rcrcrcrc
AM25LS194APC 93S47PC Beckman  899-1-R270 TI SN74LS123N
AM25LS194APC 93S47PC AM25LS163PC AM25LS164PC
AM25LS194APC 93S48PC AM25LS163PC AM25LS164PC
2000052   93427pc PROM? F 93S47PC AM25LS163PC AM25LS164PC
AM25LS09PC Beckman  899-1-R1k AM25LS151PC AM25LS164PC