Models 870 And 890 - System Clock Card; Models 870 And 890 - System Unit Backplane (Mb1) - IBM iSeries 270 Service Manual

v No: Reinstall the L3 cache module and go to L3 cache testing, procedure 2 (See page 129).
v Yes: Reject the L3 cache module, and install another L3 cache module. Then, go to L3 cache
testing, procedure 2 (See page 129).
L3 cache shorts test, procedure 5
Do MCM modules need to be installed?
v Yes: Follow MCM installation shorts test, procedure 2 (See page 127).
v No: Remove the meter and test card, and return to the procedure that sent you here.
This ends the procedure.

Models 870 and 890 - System clock card

For use by authorized service providers.
Use this procedure to remove or replace the System clock card on the Models 870 and 890.
To remove the system clock card:
1. Power off the system. See "Power on/off the system and logical partitions" on page 561.
2. Remove the MSA (air mover) enclosure. See Models 870 and 890 - MSA (air mover) enclosure.
3. Squeeze the tabs on the clock card and pull it straight out.
4. Perform a general cleaning operation using a sash brush (part number 450732) 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.
To replace the system clock card:
Note: Be sure to align the guide feature on the card with the guide feature on the system board.
1. Squeeze the tabs on the clock card and push it straight in.
2. Replace the MSA (air mover) enclosure. See Models 870 and 890 - MSA (air mover) enclosure.
3. Power on the system. See "Power on/off the system and logical partitions" on page 561.
This ends the procedure.

Models 870 and 890 - System unit backplane (MB1)

For use by authorized service providers.
Use this procedure to remove or replace the system unit backplane - MB1 on the Models 870 and 890.
CAUTION:
This unit weighs more than 55 kg (121.2 pounds). Material handling systems such as levers, slings,
or lifts are required to safely move it. When this is not possible, specially trained persons or
services (such as riggers or movers) must be used.
To remove the system unit backplane - MB1:
Attention: All components must be replaced to the location from which they were removed! Before
replacing the system unit backplane, check with your support center to ensure you have been directed to
replace the backplane by a valid error code.
Attention: This procedure requires the following:
v A safe area reserved to store parts that are removed from the system during this procedure.
v The use of a lift tool, PN 09P2481 (see the Rack Lift Tool Operation and Maintenance
Analyze hardware problems
131