IBM B50 - Manual (Page 54)

NO One of the FRUs remaining in the server is defective.
In the following order, exchange the FRUs that have not been exchanged:
1. Go to the Problem Determination Procedures (test procedures) for the
device attached to the serial port 1 connector or the display attached
to the graphics adapter, and test those devices. If a problem is
found, follow the procedures for correcting the problem on that device.
2. Graphics adapter (if installed).
3. Cable (async or graphics, including internal async cable).
4. Riser card.
5. System board (see note 3 on page 2-1).
6. Power supply.
Repeat this step until the defective FRU is identified or all the FRUs have
been exchanged.
If the symptom did not change and all the FRUs have been exchanged,
call your service support person for assistance.
If the symptom has changed, check for loose cards, cables, and obvious
problems. If you do not find a problem, return to “Step 1540-1” on
page 2-18, and follow the instructions for the new symptom.
YES Go to “Step 1540-10” on page 2-25.
2-24 7046 Model B50 Service Guide