HP 8112A Operating, Programming And Servicing Manual page 286

1 0.7-16 Servicing the Microprocessor and Front-panel
Table 1 o.7-3. Signatures for Address Drivers and Decoders
U3 U4
Pin
1
2
3 6F9A 0002
4
5 U759 9UP1
6
4868 41P4 748C PHCC
7 0356
8
9 1U5P 4FCA 3 1AC 8069
10
1 1
6U28 20UO 359H
12 P763
13
37C5 1 C66 OA8U 89C7
14 8484
15
16 FFFF 6321
17 uuuu
7791
18
The ROM can be checked using signature analysis.
ROM
1 . Set the microprocessor to free-run as described in "Free Running
Signature Analysis" and connect the signature analyzer probes as
given in Table 1 0 . 7-4.
Signature Analyzer Probe connections for ROM Test
2. Verify the reading at microprocessor +5 V supply is is 0003. If it
is not , the microprocessor is not free-running.
3. Use the data, start and stop probes to check the signatures given
in Table 10.7-5:
U14 UlO
U12 U13
uuuu
C6P l
36F8 U638 HC8A
4685 9CPH 6P25
C898
18H7 H883 P26P
2340 5HP5 26Hl
8UP9
Table 10.7-4.
Probe Trigger
\
S tart See Table 10.7-5
See Table 10.7-5
Stop f
\
Clock TP "E"
Ground Ground
U36 U17 UIS
667C
P50H
CH9U 3P76
8759
5U3F
1FH6 3P76 9H 1P
8U95
55F4 C898 9H1P
79HU 65A5
PU99
1P50
FF4H
9H1H
9UP1 CH9U
Connect to
U21
P50H
9H1H
65A5
FF4H
8759