HP LaserJet Pro 400 Service Manual - Page 141

Power-on checks, voltage. Do not plug the product into a surge protector or power strip.

Page 141 highlights

General topic Toner cartridges Transfer unit and fuser Doors Condensation Miscellaneous Questions ● Is each toner cartridge installed correctly? ● Are the transfer unit and fuser installed correctly? ● Is the front door closed? ● Does condensation occur following a temperature change (particularly in winter following cold storage)? If so, wipe affected parts dry or leave the product on for 10 to 20 minutes. ● Was a toner cartridge opened soon after being moved from a cold to a warm room? If so, allow the toner cartridge to sit at room temperature for 1 to 2 hours. ● Check for and remove any non-HP components (for example, toner cartridges or memory modules) from the product. ● Check to see whether the hardware or software configuration has changed or the problem is not associated with any specific software. ● Remove the product from the network and ensure that the failure is associated with the product before beginning troubleshooting. ● For any print-quality issues, calibrate the product. See Calibrate the product on page 137 Power-on checks When you turn on the product, if it does not make any sound or if the control-panel display is blank, check the following items: ● Verify that the product is plugged directly into an active electrical outlet that has the correct voltage. Do not plug the product into a surge protector or power strip. ● Verify that the power button is in the on position. ● Verify that the formatter is seated correctly. ● Remove any HP Jetdirect or other devices, and then try to turn the product on again. ● Ensure that the control-panel display is connected. ● Check the two fuses on the power supply. ● If necessary, replace the power supply. ● If necessary, replace the DC controller. ENWW Troubleshooting process 115

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General topic
Questions
Toner cartridges
Is each toner cartridge installed correctly?
Transfer unit and fuser
Are the transfer unit and fuser installed correctly?
Doors
Is the front door closed?
Condensation
Does condensation occur following a temperature change (particularly in
winter following cold storage)? If so, wipe affected parts dry or leave the
product on for 10 to 20 minutes.
Was a toner cartridge opened soon after being moved from a cold to a warm
room? If so, allow the toner cartridge to sit at room temperature for 1 to 2
hours.
Miscellaneous
Check for and remove any non-HP components (for example, toner cartridges
or memory modules) from the product.
Check to see whether the hardware or software configuration has changed or
the problem is not associated with any specific software.
Remove the product from the network and ensure that the failure is associated
with the product before beginning troubleshooting.
For any print-quality issues, calibrate the product. See
Calibrate the product
on page
137
Power-on checks
When you turn on the product, if it does not make any sound or if the control-panel display is blank,
check the following items:
Verify that the product is plugged directly into an active electrical outlet that has the correct
voltage. Do not plug the product into a surge protector or power strip.
Verify that the power button is in the on position.
Verify that the formatter is seated correctly.
Remove any HP Jetdirect or other devices, and then try to turn the product on again.
Ensure that the control-panel display is connected.
Check the two fuses on the power supply.
If necessary, replace the power supply.
If necessary, replace the DC controller.
ENWW
Troubleshooting process
115