HP 8112A Operating, Programming And Servicing Manual page 363

Changing the ROM
Change 42
3. For each ROM in Table B-6 connect the start and stop probes
to the indicated test point and use the data probe to check the
signature at the listed pins :
U9
ROM2
ROM:
Start/Stop: TP2
Pin
9 OA6P
10 UPlC
1 1 95FH
13 4102
14 AHUA
15 06AF
16 7000
17 4C7P
If the ROMs are changed, the data saved in the RAM has to be
made compatible with the new ROMs. This can be done by setting
the HP 8 1 12A to RCL 0 and turning the instrument off and on
again.
If the instrument becomes totally inoperable switch it off and
disconnect the RAM back-up battery for at least 30 seconds. This
will destroy the stored RAM data. Re-connect the RAM back-up
battery and switch the instrument on. The Standard Parameter Set
is now loaded into the RAM.
A change in manufacturing method introduced a part number change
for a widely used 0.47 µF capacitor.
Table B-6. ROM signatures
US U7
ROM3 ROM4 U6 ROM5 U5 ROM6
TP3 TP4
U88F 5808
70CU 60F5
6PC3 452P
3C35 7733
U623 41PU
A4HF 3HOH
2C09 P912
2125 8PF7
TP5 TP6
3HA1 P191
3HFH
61A8
03A9 OlUP
34PH H862
C3FO 61Cl
F8H8
73UF
FP6U 5U29
A795 P3F3
Backdating B-29