HP PageWriter XL M1705B Service Manual page 143

Table 6-7. Preview Display and Logic (M1700A) (continued)
Symptom
Backlight flickers.
Half screen lit.
No backlight but characters
present.
Garbled data on display.
Cause
Brightness misadjusted.
Bad connection at preview power
supply board Jl.
Burned out or weak backlight
bulb(s).
Defective power supply board.
Interconnect cable between preview
logic and display unplugged or
defective.
Defective preview logic board.
Defective CPU assembly.
Svnudom
Corrective Action
Adjust brightness knob for proper
brightness level.
Check that backlight cable is securely
connected.
Replace LCD module.
Replace board.
Ensure that plug is fully connected.
Replace cable if defective.
Replace board.
Replace CPU assembly.
Table 6-8. Keyboard and Keyboard Display (LCD)
Display stays blank.
Keys won't work. Unable to
enter data or operate controls.
Contrast or brightness misadjusted.
No +5 volts due to defective
interconnect cable.
Defective LCD assembly
Defective 5 volt regulator in main
power supply.
Interconnect cable unplugged or
defective.
Keyboard circuit board defective.
CPU assembly defective.
Corrective Action
Adjust contrast or brightness.
Replace cable assembly.
Test power supply.
Replace user interface assembly.
Replace CPU assembly.
Reconnect or replace cable.
Replace user interface assembly.
Replace CPU assembly.
6-20 Troubleshooting