IBM 6151 Maintenance And Service Manual page 388

Step 4
1.
Set the power switch on the system unit to Off.
2. Remove the memory board in slot C and record the type.
3. Install the memory board you removed from slot D in slot C.
4. Be sure the power has been off 30 seconds; then set the power
switch on the system unit to On.
5. Wait 2 minutes; then answer the following question.
IS "5c" OR "05" DISPLAYED IN THE TWO-DIGIT DISPLAY?
NO
Set the power switch on the system unit to Off.
1.
Move the memory board now in slot C to slot D.
2. Exchange the memory board that was in slot C.
3. Go to "Step 8" on page 3-9810-8.
YES
Set the power switch on the system unit to Off.
1.
Remove the memory board from slot C.
2. Look at the memory board type you recorded; then
install the original memory board in slot C.
3. Go to "Step 6" on page 3-9810-6.
3-9810-4 Service Manual