FDD-1 represents external diskette drive attached through
the external diskette drive connector. FDD-2 represents
the port replicator.
Warning: Make sure that the diskette does not have
more than one label attached to it. Multiple labels can
cause damage to the drive or can cause the drive to fail.
Do the following to select the test device:
1. Select the advanced diagnostics mode and select
Tool; then select the FDD-1 or FDD-2 icon and press
the spacebar. A √ mark appears next to the selected
icon. Insert the blank diskette when instructed.
2. Run the diskette drive test.
3. If the controller test detects an error, FRU code 10
appears. Replace the system board.
4. If the controller test runs without errors, the drive
read/write tests start automatically.
5. If the drive test detects an error, FRU code 50 for
FDD-1 or 51 for FDD-2 appears. If the diskette itself
is known to be good, replace the drive.
6. If FDD-2 test detects an error, move the drive to the
computer's diskette drive connector directly, if
possible, and test it again as FDD-1.
If no errors occur in the FDD-1 position, the drive is
not defective. Go to “Port Replicator Checkout” on
page 275 to isolate the replicator problem.

Status Indicator Checkout

If an LED problem occurs, do the following:
1. Power off the computer
2. Power on the computer
3. All the LEDs in the indicator panel turn on for a
moment soon after the computer is powered-on.
Make sure that all LEDs turn on.
If the problems remains, replace the system board.
Power Systems Checkout
To verify the symptom of the problem, power on the
computer using each of the power sources as follows.
1. Remove the battery pack and diskette drive.
2. Connect the AC Adapter and check that power is
supplied.
3. Disconnect the AC Adapter and install the charged
battery pack; then check that power is supplied by the
battery pack.
If you suspect a power problem, see the appropriate power
supply check listed below.
“Checking the AC Adapter” on page 273.
“Checking Operational Charging” on page 273.
“Checking the Battery Pack” on page 274.
272 IBM Mobile Systems - ThinkPad HMM Volume 3