Chapter 4. Troubleshooting Common Problems - IBM 4851 514 Planning, Installation And Service Manual

Updated October, 2008

Chapter 4. Troubleshooting common problems

This section describes several common problems and explains what to do.
Table 9. Symptoms and actions
If the problem is...
No green power light on the
tower unit.
Operator display exhibits the
following conditions (with the
green LED on):
v Blank screen
v No cursor available
v Screen is unreadable
v Other display problems
Operator display backlight:
dark, dim, or partially lit.
© Copyright IBM Corp. 2005, 2008
Here's what to do.
1. Ensure that the system unit is plugged into a working
electrical outlet and replug the power cable at the power
supply.
2. Verify that the display cable is plugged properly into the
display and into the system board.
3. Verify the power cable is plugged into the system board
connectors P1 and P2.
4. Replace the power supply. See "Power supply –
removing and replacing" on page 68.
5. Replace the system board. See "System board –
removing and replacing" on page 66.
1. Adjust the brightness control at the bottom right side of
the display.
2. Ensure that the operator display cable is securely
connected.
3. Switch unit off and back on.
4. Run the operator display test using the diagnostic USB
memory key.
5. Open the tablet and check that all of the cable
connections are secure.
6. Replace the LCD assembly. See "LCD assembly -
removal and replacement" on page 59.
7. If condition persists, replace the tablet card. See "Control
card - removal and replacement" on page 57.
8. If condition persists, replace the system board. See
"System board – removing and replacing" on page 66.
1. Adjust the brightness using the button located on the
front of the display.
2. Ensure operator display cable is securely attached under
display tablet and at system board.
3. Open the tablet and check that all of the cable
connections are secure. Reboot the system.
4. If only half of the display is lit, replace the LCD assembly.
See "LCD assembly - removal and replacement" on page
59.
5. If condition persists, replace the system board. See
"System board – removing and replacing" on page 66.
6. If condition persists (the operator display backlight is dark
dim or partially lit); however, the HDD light shows activity;
and the POST bleeps completion upon reboot, replace
the LCD assembly. See "LCD assembly - removal and
replacement" on page 59.
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