HP 3562A Service Manual page 542

S E RV I C E
Et If the signatu res are correct, go to test e, D is p l ay DMA Word Cou nters. I f
any signatu res are incorrect, check the correspond ing address cou nter output.
If the s ignatu re is correct at the word cou nter and i n co rrect at the d r iver,
the p roblem is a board trace or solder j o int. If the si gnatu re is also i n co rrect
at the word cou nter, proceed with step d, Disp lay DMA Add ress Cou nters.
d . D i s p l ay DMA Address Cou nters
Perform this test only if a f a i l u re was found in perform ing the signature analysis
in tab l e A8-4. T h i s test ve rifies that the add ress counters are load ing correctly.
If load ing fai l s, either a d ata receiver, cou nter, or board trace is the probab le
cause of the fa i l u re.
Et I f j u m p ers A8 J 3 and J4 are not i n the normal (N) pos ition, turn off power,
m ove j u m pers to normal position, and turn power on.
Et Press the fol lowing key seq uence on the H P3562A:
SPCl fCT N
The A2 L E Ds s h o u l d d is p l ay hex B8.
8-92
Table AB-4 Display Controller Signature
Analysis Test #2
Signal
N ame IC (Pin)
Address
D rivers:
I n puts:
U604(1 1 )
(1 2)
(1 3)
(1 4)
(1 5)
(1 6)
(1 7)
(1 8)
U 605(1 1 )
(1 2)
(1 3)
(14)
(1 5)
(1 6)
(1 7)
(1 8)
S E RV I C T E ST
(52)
Signature
U U U U
5555
CCCC
7F7F
5 H21
OAFA
U PFH
52F8
HC89
2 H 7O
H PPO
1 293
HAP7
3C96
3827
755U
T E ST
M E MORY D S P I N T
(52) T E ST 1 (53)
MOD E L 3562A