Service Approach; Before Performing Service; After Performing Service; Post-Service Test - HP LaserJet PRO M521 Repair Manua

Service approach

Product repair normally begins by using the product internal diagnostics and the following two-step
process:
1. Isolate the problem to the major system (for example, the network, the server, or the product).
2.
Troubleshoot the problem by using the procedures in the solve problems chapter of the
Troubleshooting Manual.
After you find a faulty part, the product can usually be repaired at the assembly level by replacing field-
replaceable units (FRUs). Some mechanical assemblies might need to be repaired at the subassembly
level.

Before performing service

Remove all paper from the product.
●
Turn off the power using the power switch.
●
Disconnect the power cable and interface cable or cables.
●
Place the product on an ESD workstation or mat, or use an ESD strap (if one is available). If an
●
ESD workstation, mat, or strap is not available, ground yourself by touching the sheet-metal
chassis before touching an ESD-sensitive part.
Remove the toner cartridges. See
●
Remove the tray or trays. See
●

After performing service

Connect the power cable.
●
Reinstall the toner cartridges.
●
Reinstall the tray or trays.
●
If an optional paper feeder was installed, place the product on the feeder.
●

Post-service test

Perform the following test to verify that the repair or replacement was successful.

Print-quality test

1.
Verify that you have completed the necessary reassembly steps.
2.
Make sure that the tray contains clean, unmarked paper.
3.
Attach the power cable and interface cable or interface cables, and then turn on the product.
4. Verify that the expected start-up sounds occur. The fans start.
ENWW
Toner cartridge on page
Tray 2 or Tray 3 assembly on page
11.
13.
Service approach
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