IBM ThinkPad 340 Series Hardware Maintenance Manual page 352

Infrared Related Symptoms
Symptom/Error
Unable to communicate
using the Infrared (IR) Port
Intermittent Problems
Intermittent system hang problems can be caused by a
variety of reasons that have nothing to do with a hardware
defect such as: cosmic radiation, electrostatic discharge, or
software errors. FRUs replacement should only be
considered when a recurring problems exits.
When analyzing the intermittent problem, do the following:
1. Run the advanced diagnostic test for the system
board in loop mode at least 10 times.
2. If no error is detected, do not replace any FRUs.
3. If any error is detected, replace the FRU shown by
the FRU code. Rerun the test to verify that no more
errors exist.
342
IBM Mobile Systems HMM
FRU/Action
1. Make sure the setup
for the IR is correct.
2. Make sure there are
no fluorescent lights
near the computer.
The computer may
receive electrical noise
from the fluorescent
light.
3. Run the advanced
diagnostic test. If an
error occurs and a
FRU code is displayed,
replace the parts
shown by the FRU
code.
4. For Model 755CDV, if
the remote control is
enabled, the
communication with
the IR port is disabled.
Run the Mind Path
Presentation F/X
program and set the
infrared to OFF; then
observe the symptom.