IBM 6151 Maintenance And Service Manual page 372

Step 2
1. Set the power switch on the system unit to Off.
2. Remove the top cover. If needed, see Section 4.
3. Unplug the external power cable to the system unit.
4. Disconnect the large power connector from the system board,
the power connector from the fixed-disk drive, and the power
connector from the diskette drive.
5. Plug in the external power cable to the system unit.
6. Set the power switch on the system unit to On.
7. Wait 15 seconds; then answer the following question.
IS THE POWER-ON INDICATOR ON?
NO Go to "Step 6" on page 3-8800-6.
YES Continue On the next page.
3-8800-2 Service Manual