IBM 7012 300 Series Installation And Service Manual page 48

Step 5
(from Step 4)
The failure may be caused by a defective SIMM on the last memory card installed. To
isolate the failing SIMM in a pair of SIMMs, do the following:
1. Set the power switch on the system unit to Off. Using a pair of operational SIMMs for the
type of memory card used, install the pair of SIMMs in locations 1 and 2 on one of the
suspected memory cards.
2. Set the power switch on the system unit to On. If operational, the system will stop and
two or more numbers with values between 221 and 296 are displayed alternately in the
three-digit display, or a solid 262 will be displayed.
For Models 340, 34H, 350, 355, 360/36T, 365, 370/37T, and 375, 380, 390, 39H, and
397, the system stops with a value of 243 for up to six minutes and then changes to to a
value of 262.
3. If the system still fails, continue testing the SIMMs in pairs (locations 3 and 4, 5 and 6, 7
and 8) until the system does not fail, or all the SIMMs on the suspected memory cards
have been tested.
Were you able to isolate the failed pair of SIMMs?
NO
YES
2-1540-6
Installation and Service Guide
Exchange the memory card. If this does not correct the problem, go to Step
6.
Go to "Map 0410: Repair Checkout" in the POWERstation and
POWERserver Common Diagnostics and Service Guide.