The table following lists all of the logic boards found in machine number M2971, all of the markings on the front and rear sides, and a count of the transistors and diodes on each.
The boards are all 9" wide and are made from single-sided phenolic material. Boards 1 to 4 are 3" high and are mounted vertically at the front of the machine, under the display tube panel. Boards 5 to 10 are 4" high and are mounted vertically in the central section of the card cage. Boards 11 to 20 are 2" high and are mounted horizontally at the rear of the machine (listed from top to bottom). Boards 1 to 10 plug in to the base board in the bottom of the machine, while boards 11 to 20 plug into a vertical backplane which itself plugs into the baseboard. The horizontal and vertical card cages are closely spaced at three cards to the inch.
The boards have a component overlay printed in white, although some appear to have an "optional" section printed in yellow. The board names are generally on the copper side, and give a rough idea of the logical structure of the machine.
Altogether, the machine contains about 250 discrete transistors, and over 1300 diodes. There are three pairs of MA09 and MA15 ICs on the Register board (one pair in the yellow section), and a single MA09 on the Function Counter board.
There is no guarantee that the boards listed are original, or even correct for this model. The machine is over 35 years old, and may well have had board replacements at various times during its long working life. I would welcome confirmation of similarities, or advice of differences, from owners of other 1000-series machines.
| No. |
Description | Front (component overlay) |
Front (pencil) |
Back (copper) |
TA No. |
Trans |
Diode |
| 0 |
Base Board |
22 JAN 1970 |
998PC Issue 2 |
TA 7155 |
0 |
0 |
|
| 1 |
Master Oscillator |
E 890CD Issue 4 |
5/8159 |
890PC Issue 6S |
TA 7057 |
16 |
23 |
| 2 |
Complementer |
C 889CD Iss 5 |
6/8797/P |
889PC Issue 5 |
TA 7058 |
12 |
13 |
| 3 |
Register |
F 1019CD/W Iss 5 TAU5191 White 1019CD/Y Iss 2 TAU5193 White & Yellow |
1019PC Issue 3 |
TA 7171 |
22 |
10 |
|
| 4 |
Carry Store |
G 881CD/W Iss 4 TAU5043 White 881CD/Y Iss 2 TAU5164 White & Yellow 16 FEB 1970 |
881PC Issue 2 |
TA 7061 |
17 |
23 |
|
| 5 |
Display |
K 1083CD Iss 2 4 FEB 1970 |
1083PC Iss 3 |
TA 7194 |
37 |
18 |
|
| 5A |
Number Tube Panel |
11/4643/P |
11/4643/P |
943PC Issue 5 |
TA 7074 |
0 |
0 |
| 6 |
Timer |
T 883CD Issue 3 |
12/9176/P |
883PC Issue 1 |
TA 7053 |
29 |
19 |
| 7 |
Buff. Stat. |
13/1762/P |
13/1762/P |
8?27PC Iss1 |
TA 7054 |
34 |
61 |
| 8 |
Slip & DP |
H 926CD Iss 4 |
14/8695 |
926PC Iss 2 |
TA 7055 |
28 |
37 |
| 9 |
Function Counter |
D 915CD Iss 7 |
15/8820P |
915PC Issue 6 |
TA 7056 |
18 |
29 |
| 10 |
Memory Logic |
LM 996CD Iss 4 |
30/2926 |
996PC Issue 6 |
TA 7176 |
16 |
167 |
| 11 |
Bistable Logic |
LA 916CD Issue 2 TA7066 |
27/5306/P |
916PC Iss 3S |
TA 7066 |
21 |
19 |
| 12 |
Display Logic |
LB 1045CD Iss 2 |
20/7732/P |
1045PC Iss 2 |
TA 7184 |
2 |
87 |
| 13 |
Index Logic |
LC 1046CD Iss 3 |
21/7083/P |
1046PC Iss 1 |
3 |
76 |
|
| 14 |
Services Logic |
LD 1047CD Iss 2 |
23/10873/P |
1047PC Iss 1 |
TA 7182 |
0 |
95 |
| 15 |
Add/Subtract |
LE 918CD Iss 6 TA7063 |
24/5815 |
918PC Iss 4S |
TA 7063 |
4 |
113 |
| 16 |
Copy Logic |
LF 1041CD/Y Iss 2 1011 TA7186 |
24/3440/P |
1041PC Iss 3 |
TA 7186 |
3 |
113 |
| 17 |
Divide Logic |
LG 1042CD Iss 2 |
22/5352/P |
1042PC Iss 1 |
TA 7180 |
3 |
117 |
| 18 |
Multiplier Logic |
856CD Iss 6 |
25/6327/P |
TA7053 |
TA 7053 |
2 |
95 |
| 19 |
Sundries |
LJ 1048CD Iss4 11 FEB 1970 |
TA7185 Iss 2 |
TA 7185 |
3 |
92 |
|
| 20 |
R-O & % |
LK 868CD Iss 2 |
29/5510/P |
868PC Iss 1 |
TA 7159 |
3 |
97 |
