HP 4262A Operating And Service Manual page 209

Model 4262A
Set A2381 to OFF
Window Test
C positions.
START "\ A23PA9
STOP _/_ A23PA9
CLOCK ./~ A22TP2
+5V PPPO?
Nanoprocessor
Direct Control
Bus Stuck?
Device Select
"Write" Bus Stuck ?
Troubleshoot
Stuck Bus.
Check A23U3, Program Address
Bus Stuck?
Check A23UL.
Device Select
Bus Stuck?
Check A23U1L,
START T\_ A23PA9
Window Test YES 15 Signature Set 6 \YES
(:)——- STOP ./~ A23PAG Go to Flow Diagram D,
CLOCK -~ A22TP2 8V 5CAU? OK?
NO NO
i
@ Nanoprocessor \YES Troubleshoot
Data Bus Stuck? Stuck Bus.
NO
Check A23V1.
Device Select
"Read" Bus Stuck ?
Device Select
Bus Stuck?
Check A23UL
Troubleshoot
Stuck Bus.
Set 4 \YES () oo to flow diagram below.
Check 423U4.
Section VIII
Figure 8-19
Figure 8-19. Digital Section Troubleshooting Procedures.
Flow Diagram C. A28 Board Diagnostic Flow Diagram.
(Nanoprocessor and Device Select Decoder)
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