Faults That Are Difficult To Diagnose - Epson MR Series Technical Reference Manual

5. For problems with the keyboard, confirm whether replacing the MSR assembly solves
the problem.
6. For problems with the COM3 port, confirm whether replacing the COM cable solves the
problem.
7. For problems with the COM3 or COM4 port, confirm whether replacing the COM port
circuit board solves the problem.
8. For problems with the COM3 or COM4 port, confirm whether replacing the riser circuit
board solves the problem.
9. Confirm whether replacing the main circuit board solves the problem.

Faults that are Difficult to Diagnose

System Halts on an Intermittent Basis
❏ Follow the procedures below.
1. Visually confirm that the CPU cooling fan is functioning properly at normal speed. If it
stops, confirm whether replacing the CPU fan solves the problem.
2. Visually confirm that the system fan is functioning properly at normal speed. If it stops,
confirm whether replacing the system fan solves the problem.
3. Visually confirm that the power supply fan is functioning properly at normal speed. If it
stops, confirm whether replacing the power supply unit solves the problem.
4. Check whether the CPU and DIMM(s) are properly installed.
5. Check the connectors for the HDD, CD-ROM, and FDD.
6. Check the other internal connectors for the IM-800.
7. Confirm whether replacing the main circuit board solves the problem.
8-16 Troubleshooting Rev. I