HP 3562A Service Manual page 490

S E RV I C E
3. Verifies check ROM. The correct checksum resu lts for all ROMs are stored at designated
locations in the l ast ROM p a i r. T h i s step reads and verifies the co ntents of those
locations. If this test fa i l s, one or both of the last ROM pair are the l i kely cause.
4. Checksu m s high and low bytes of ROM. The c hecksum resu lts are compared to the
correct val ues stored in mem ory.
Test
Failed
1
1
1
2
2
2
2
2
2
3
3
3
4
4
4
4
4
4
4
4
* This fai l u re code may result from defective A8 U 1 01 or A8 U201 as wel l as
from a ROM data bus problem.
* * See tab l e A3-2 to decode I C n um ber.
* * * It is u n l ikely that both ICs i n a ROM pair are fau lty. The most l i kely cause of this
fai l u re is a fau lty IC enable signa l .
8-40
Table A3-1
LED
Bank
87 System Bus fai l u re, high byte
88 System Bus fai l u re, low byte
System Bus f a i l u re, both bytes
89
8A ROM Bus failu re, low byte *
R O M B u s f a i l u re, high byte *
8 B
8C ROM Bus fai l u re, both bytes *
7A ROM Bus fai l u re, low byte
7 B R O M B u s fai l u re, h igh byte
7C ROM Bus failu re, both bytes
SA Check ROM f a i l u re, low byte
5 B Check ROM fa i l u re, high byte
5C C heck ROM f a i l u re, both bytes
40 to 53 ROM I C fai l u re, low byte **
20 to 33 ROM IC fai l u re, h igh byte * *
ROM IC fai l u re, both bytes * * *
60 to 73
ROM ICs, m u lti p l e f a i l u res h igh byte
84
85 ROM ICs, m u ltiple failures low byte
86 ROM I Cs, m u ltiple fai l u res both bytes
8 D N o ROM passes checksum, system data
bus good; check system address bus.
Program ROM and System Bus tests pass.
1 F
This is a normal annunc iation.
A2 LED Display Codes
Probable Failure
MOD E L 3562A
Other
Information
System
b u s
good
N o information
about system
bus
ROM
b u s
good
System
bus
good