HP 3562A Service Manual page 544

S E RV I C E
• Turn power off.
Move j u m pers A8J 3 and A8J 4 to normal (N) position.
•
f. I f these tests pass, the cause of fai l u re is probably on the A1 7 D i s p l ay I nterface
board .
2. D i s p l ay I nterface
Because of the relative cost of the A 17 board and troubleshooting time, it is recom mended
that this board be rep l aced if defective.
3. G l obal RAM
Setu p for G l obal RAM tests
a.
Turn off power.
•
• Move A8J 5, J 6, J 7, J 8, and J9 to test (T) pos ition. J u mper J 5 d iscon nects the
memory request l i nes from the arb iter and routes the output from the refresh
add ress cou nter i nto the arb iter. T h i s gene rates every pos s i b l e com b i nation
of requests to the arb iter. The other j u m pers affect various control l i nes (see
schematic, f ig u re 9-A8a).
• Connect the signat u re ana lyzer accord ing to tab le A8-6.
8-94
Table AS-5 Display Controller Signature
Analysis Test #3
Signal
IC (Pin)
Name
Word
Cou nter
Outputs:
U400(1 5)
(14)
(1 3)
(1 2)
(1 1 )
U401 (1 5)
(14 )
(1 3)
(1 2)
(1 1 )
U501 (14)
(1 3)
(1 2)
(1 1 )
Signature
P762
U U U P
5554
CCCA
7F7H
6F9C
5 H20
OAFC
U PFF
52F9
HC88
2 H 71
H PP1
1 292
MOD E L 3562A