Mh Led Indicator Troubleshooting Flowchart - HP 7925D Service Manual

Troubleshooting
Replace PCA·A4. If malfunction remains,
check that correct head select si~nals are
active at A4Pl-12 (HSO), A4Pl·13 (HS1).
A4Pl-R (HS21. and A4P2·3 (HS3).
Replace PCA-A6. If malfunction remains,
check following circuit paths for short to
ground:
A4P1·11 to A6P1·2
A4P1·10 to A6P1·C
A4P1·9 to A6P1-3
A4P2·T to A6Pl-J
NOTES:
1. Refer to the following diagram for circuit details.
• Read/Write System Functional Diagram, fig. 4·28.
2. PCA's associated with MH malfunction include:
• I/O sector PCA·A2/Microprocessor.
• Drive control PCA·A4.
• Read/Write PCA·A6.
Replace PCA-A2. If malfunction remains,
check following current paths for open cir-
cuit:
A2P1-N to A4P1-12
A2P1-12 to A4P1-13
A2P1-P to A4P1·R
A2P l-S to A4P2-3
7925
7311-10A
4-18
Figure 4-8. MH LED Indicator Troubleshooting Flowchart