IBM iSeries 270 Service Manual page 112

Attention: The L3 modules in this system can be attached to the backplane a maximum of three times. If
an L3 module is removed for a fourth time, it must be replaced with a new L3 module. Check the
MCM/L3 Label Map to determine how many times the module has been removed before. New L3 cache
modules are shipped with a new MCM/L3 plug count adhesive replacement label. When you install a new
L3 cache module, place the new label in the correct position on the MCM/L3/passthrough tri-fold plug map.
To remove L3 modules:
Attention: If more than one module is to be replaced or reseated, begin with the topmost module, replace
it and then go to the next highest position module, until the lowermost module has been replaced or
reseated.
1. Power off the system and unplug the power cord. See Power on/off the system and logical partitions.
2. Remove the MSA (air mover) enclosure. See Models 870 and 890 - MSA (air mover) enclosure.
3. Perform a general cleaning operation using a sash brush (part number 450732), (not the one
included with the FRU kit) and vacuum cleaner to remove any accumulated dust and debris that has
settled in the processor subsystem. Hold the vacuum hose near the brush to remove any debris the
brush generates.
4. Arrange the four 4-position trays on the ESD mat in a pattern that corresponds to the positions of the
L3 modules on the system.
Attention: Each L3 module must be returned to the location from which it was removed.
5. Note the location of the module being removed. Check the MCM/L3 Label Map sheet on the system
to confirm the number of times the target module has been unplugged. If three times, order a new
module. If this is the first removal/reseat for the module, record the serial number of the module and
the date of the action.
6. Use a 5mm socket wrench to loosen the screw in the center of the L3 module spring plate.
Figure 1. An L3 cache module
100
Hardware (Remove and Replace; Part Locations and Listings)