IBM 6151 Maintenance And Service Manual page 383

Step 13
1. Set the power switch on the system unit to Off.
2. Remove the failing option or adapter from the system unit.
3. Remove the additional FRUs.
4. Install the failing option or adapter back in the system unit.
5. Set the power switch on the system unit to On; then wait 15
seconds before answering the following question.
AJZB159
IS THE POWER-ON INDICATOR ON?
NO Exchange the failing option or adapter; then continue on
the next page.
YES One of the additional FRUs you removed is failing. If only
one FRU was removed, exchange it. Otherwise, install the
FRUs one at a time until you identify the failing FRU; then
exchange it and continue on the next page.
(6/88) Problem Isolation Charts 3-8800-13