IBM System x3650 M3 4255 Service Manual page 75

v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 4, "Parts listing, Types 4255, 7945, and 7949 server," on page 157 to determine which
components are customer replaceable units (CRU) and which components are field replaceable units
(FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
v Go to the IBM support Web site at http://www.ibm.com/systems/support/ to check for technical
information, hints, tips, and new device drivers or to submit a request for information.
Symptom
The OVER SPEC LED on the
light path diagnostics panel is
lit, and the 12v channel C LED
on the system board is lit.
The OVER SPEC LED on the
light path diagnostics panel is
lit, and the 12v channel D LED
on the system board is lit.
Action
1. Disconnect the server power cords.
2. Remove the following components:
v Tape drive, if one is installed (see "Removing a tape drive" on page 214for
more information)
v SAS riser-card assembly
v DIMMs 1 through 9
v (Trained service technician only) Microprocessor 1
3. Move switch 2 on switch block 4 (SW4) to the On position to force power on;
then, restart the server. If the OVER SPEC and 12v channel LEDs are still lit,
(trained service technician only) replace the system board.
4. Reinstall the components listed in step 2 one at a time, in the order shown,
restarting the server each time. If the 12v channel C LED is lit, the component
that you just reinstalled is defective. Replace the defective component.
v (Trained service technician only) Microprocessor 1
v DIMMs 1 through 9
v SAS riser-card assembly
v Tape drive, if one is installed (see "Installing a tape drive" on page 216 for
more information)
1. Disconnect the server power cords.
2. (Trained service technician only) Remove microprocessor 1.
3. Move switch 2 on switch block 4 (SW4) to the On position to force power on;
then, restart the server. If the OVER SPEC and 12v channel LEDs are still lit,
(trained service technician only) replace the system board.
4. (Trained service technician only) Move switch on switch block back to the Off
position; then, reinstall microprocessor 1.
5. Restart the server. If the 12v channel D LED is lit, (trained service technician
only) replace microprocessor 1.
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Chapter 3. Diagnostics