If the external display does not meet these specifications,
replace the external display.
If the external display meets these specifications, replace
FRUs in the following order one at a time until the problem
is corrected.
Note: If the replaced parts did not resolve the
problem, put the original parts back in the IBM
ThinkPad Dock I. Do not replace
non-defective parts.
If the external display is attached to IBM ThinkPad
Dock I:
1. Main card of IBM ThinkPad Dock I
2. External display
If the external display is attached to the display
adapter:
1. Display adapter
2. Main card of IBM ThinkPad Dock I
3. Riser card
4. External display

External Keyboard

Notes
If a mouse or other pointing device is attached,
remove it and see if the error symptom goes
away. If the symptom goes away, the mouse or
other pointing device is defective.
The computer keyboard does not work when an
external keyboard is connected.
1. Power-off the computer.
2. Disconnect the keyboard cable from the external
keyboard.
3. Power-on the computer and check the keyboard cable
connector for the following voltages. All voltages
have a ±5% voltage tolerance.
4531
26
Pin
1
2
3
4
5
6
+5.0
Ground
+5.0
+5.0
Voltage (V dc)
Not Used
Not Used
4. If all voltages are correct, replace the external
keyboard.
5. If the voltages are not correct, replace the following
FRUs one at a time until the problem is corrected.
556 IBM Mobile Systems - ThinkPad HMM Volume 3