HP 3562A Service Manual page 543

MOD E L 3562A
The display will blank during the Displa y Interface tests and the
special function menu will disappear.
Move j u m pers ABj 3 and ABj4 to the test (T) positi on.
•
• Press softkey 54 (A2 L E Ds d i s p l ay B9). T h i s loads a hex A i nto each of the
four d i s p l ay add ress cou nters (AB U600 through U603).
• Probe the output p i ns of U 600 through U603 . The output of each cou nter
should be hex A (b i nary 1 01 0, p i n s 1 1 , 1 2 , 1 3, and 1 4).
Turn off power.
•
Move j u mpers ABj 3 and ABj4 to the normal (N) position .
•
• Turn on power.
• Press the 3562A keys as fol l ows:
SPCl FeTN
A2 L E Ds shou ld d isplay hex BB
• Move j u m pers ABj 3 and ABj4 to the test (T) pos ition.
• Press softkey 55 (A2 L E Ds d is p l ay BA). T h i s l oads a hex 5 i nto each of the
D i s p l ay Address Cou nters (U600 through U603), toggl i n g each bit from the
previously loaded hex A.
• Probe the output p i n s of U600 through U603. The output of each cou nter
s h o u l d be hex 5 ( b i nary 01 01 , p i n s 1 1 , 1 2, 1 3, and 1 4).
Turn off power.
•
Move j u m pe rs ABj 3 and ABj 4 to the normal (N) positi on.
•
e. D i s p l ay DMA Word Cou nters
Check U501 p i n 1 5 (TC L). The sig nature shou ld be 6U29. If this s ignature
•
is incorrect, check the signatures i n table AB-5. If any word cou nter signatu res
are i n correct, verify that d ata is getting to the cou nter i n puts and that the
signal WLOA D L is togg l i ng.
NOTE
. . . . . . 5 E RV I C T E 5T
(52)
T E 5T
MEMORY D5 P I NT
(52) T E ST 1 (53)
S E RV I C E
B-93