HP 8112A Operating, Programming And Servicing Manual page 362

Decoder
GPIA CS
Keyboard
LB
ADD
READ
LATCH l
HP-IB
RAM-SEL
ROM
B-28 Backdating
Table B-5. Sub Decoder Signature Analysis
Sub Free Run UlO U l l U13 U14 U15 Ul6 UIS U19 U23 U26 U30 U37
S.A. Pin Pin Pin Pin Pin Pin Pin Pin Pin Pin Pin Pin
748C
U638
89C7
C898
6P25
HCSA
PHCC
8UP9 8 8
5HP5
OASU
H883
9 .
In Chapter 10.7 modify the section on trouble-shooting the ROM
as follows:
The ROMs can be checked using signature analysis:
1 . Set the microprocessor to free-run as described in Chapter 10. 7
and connect the signature analyzer probes as instructed.
Signature Analyzer Probe connections for ROM Test
2. Connect the data probe to the +5 V supply and check that the
signature is P254. If not , the microprocessor is not free-running.
7
10
14 1 1
12 1 1
1 1
10
7
15 9
14
10
1 1
13
Probe Trigger Connect to
\
Start See Table B-6
f
Stop See Table B-6
\
Clock
TP "E"
Ground
Ground
3
7
1 / 1 9
1 1
9