Lenovo ThinkPad 370 Hardware Maintenance Manual - Page 352

Infrared Related Symptoms Symptom/Error FRU/Action Unable to communicate using the Infrared (IR) Port 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. 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