HP 8112A, Operating, Programming And Servicing Manual

Page: 287 / 406

Table 1 0.7-5. ROM U40 signatures
Data probe Connect Start/Stop probes to Ul2 pin:
U140 pin
7 9 10 11 12
1 1 P191 3HA1 5808 U88F
OA6P
12 618A 3HFH 60F5 70CU
UPlC
13
OlUP 03A9 452P 6PC3 95FH
15
H862 34PH 7733 3C35 4102
16 61Cl C3FO 41PU U623 AHUA
17 F8H8 73UF 3HOH A4HF 06AF
18 5U29 FP6U P912 2C09 7000
19 P3F3 A795 8PF7 2125 4C7P
Changing the ROM
If the ROM is changed, the data saved in the RAM has to be made
compatible with the new ROM. This can be done by setting the HP
8 1 12A to RCLO and turning the instrument off and on again.
If the instrument becomes totally inoperable switch it off and
disconnect the RAM back-up battery
(
by removing W2 jumper
)
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.
Keyboard
The keyboard can be checked using signature analysis:
1 . Set the microprocessor to free-run as described in "Free Running
Signature Analysis" and connect the signature analyzer probes as
given in Table 10.7-2.
2. Verify the reading at micropro5 V supply is is 0003. If it
is not, the microprocessor is not free-running.
3. Connect the data probe to TP7, on the microprocessor board A3,
and check the signature obtained when each key is pressed against
Table 10. 7-6.
Servicing the Microprocessor and Front-panel 1 0.7-17