IBM 270, Service Manual

Page: 106 / 622

To replace the bulk power controller (BPC):
1. Ensure that all of the BPR’s on-lock/off-unlock switches are in the off position on this BPA before
proceeding.
2. Slowly slide the unit into the slot and seat it carefully against the backplane, avoiding damage to the
connectors.
3. Tighten the left and right thumb screws with the torque tool (PN 6422789).
4. Ensure that the Unit Emergency Power Off (UEPO) bypass switch, on the BPC front panel, is in the
’normal’ position.
5. Plug all cables into the BPC according to cable labeling.
6. Turn on (left) all of the BPR’s on-lock/off-unlock switches.
7. To indicate completion of these steps, press the (white) Service Complete button on the UEPO panel.
The BPA will automatically configure while it is energized.
This ends the procedure.
Models 870 and 890 - Bulk power distribution (BPD)
For use by authorized service providers.
Use this procedure to remove or replace the bulk power distribution (BPD) on the Models 870 and 890.
There are two BPD positions located immediately above the bulk power controller (BPC). The upper most
position is featurable, and if it is not used an appropriate air flow baffle must be inserted. See “Locations
— Models 870 and 890 with an FC 9094 Base I/O Tower” on page 284.
To remove the bulk power distribution (BPD):
1. Do not power down the system if it is powered on; this procedure can be done concurrently.
2. Locate the BPD to be replaced by decoding the SRC (see System reference codes), or see Locations
— Models 870 and 890.
3. Open the cover to access the field replaceable unit (FRU). See “Models 870 and 890 - Covers” on
page 97.
4. Note the state of the BPD’s LED. Then, press the (green) Start Service button on the UEPO panel,
and only proceed if the LED is off or the repair has been scheduled (System outage - EPO off).
5. Locate the bulk power regulator (BPR) on the affected bulk power assembly (BPA). Manually turn off
(to the right) the BPR’s on-lock/off-unlock switch on these BPRs.
6. Verify that all cables are labeled for plug location, and then unplug the cables from the BPD.
7. Loosen the left and right thumb screws using the torque tool (PN 6422789), and slide the unit out of
the slot. This is the same way to remove the bulk power baffles (BPBs).
Note: The BPD weighs approximately 5 pounds.
To replace the bulk power distribution (BPD):
1. Important: Ensure that all BPR’s on-lock/off-unlock switches are in the ’off’ position on this BPA before
proceeding.
2. Slowly slide the unit into the slot and seat it carefully against the backplane to avoid damaging
connectors.
3. Tighten the left and right thumb screws with the torque tool (PN 6422789).
4. Plug all the cables to the BPD, ensuring correspondence of plug locations and cable labeling.
5. Manually set all BPR’s on-lock/off-unlock switches to the ’on’ position (to the left) contained in the
associated BPA.
6. To indicate completion of these steps, press the (white) Service Complete button on the UEPO panel.
This ends the procedure.
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Hardware (Remove and Replace; Part Locations and Listings)