T Led Indicator Troubleshooting Flowchart - HP 7925D Service Manual

Troubleshooting
, 7311-14A
4-22
NOTES:
1. Refer to the following diagrams for circuit details.
• Head Positioning System Functional Diagram.
fig. 4-26.
• Mainframe Assembly Wiring Diagram, fig. 4·23.
2. PCA's associated with T malfunction include:
• Servo PCA·A3.
• Drive control PCA-A4.
Refer to head positioning troubleshooting
flowchart, fig. 4·20.
Refer to CRB troubleshooting flowchart,
fig. 4·21.
RET signal occurred and CRB signal did not
become active within 1.66 sec.
Replace PCA-A3. Refer to CRB trouble-
> - - - - - - - - - - - - r - - - - - - - - - . t
shooting flowchart, fig. 4·21.
Neither slew reverse nor emergency retract
circuits retract carriage when they should.
Place piece of opaque material in carriage
back detector slot to block light from photo-
+-
~
rans/stor. Again check voltage at terminal
with white wire.
Figure 4-12. T LED Indicator Troubleshooting Flowchart
7925