IBM FlashSystem 900, Service Manual

Page: 518 / 546

FRU Exchange
Exchange a Transformer
Important
Check that the 'Power Control' display is
set to local (3) on the control panel.
If not, do the following:
¹
Press the 'Power Control' key until (3) is
displayed in the power control window.
¹
Press the 'Validate' key.
If the state of the machine does not allow you
to display or to change the 'Power control'
mode, continue with the following procedure.
Note
Two persons are necessary to move a trans-
former.
To exchange a transformer, you must first remove
its associated ACPW.
1. Locate the transformer that you have to
exchange and its associated ACPW, using
Figure 4-9 on page 4-8 and Figure 4-10 on
page 4-9.
2. If the machine has its:
¹
Ready LED ON, go to step 3.
¹
Otherwise, go to step 7.
3. Check if there is another ACPW or DCPW in
your 3746-900.
If yes, go to step 6.
If not, proceed with the next step.
4. Press the 'Stand-by' key.
5. When the machine is in standby mode with its
Standby LED ON, go to step 7.
6. Activate the maintenance switch.
a. Open the front cover and locate the lever
of the maintenance switch on the
DCDP.
.1/
b. Pull the lever outwards.
This will prevent the main -48v from drop-
ping and will stop the power monitoring.
7. Switch the main circuit breaker CB1 OFF at
the 3746-900 primary power box associated
with the transformer that you exchange.
.2/
8. Unplug the J1 connector from the ACPW.
9. At the rear of the machine loosen the four
screws which secure the transformer cover
plate.
10. Remove the transformer cover plate.
11. Unplug the power cord from the J2 connector
of the ACPW associated with the transformer
that you want to remove.
.3/
12. Check that on the transformer there is no
voltage between TB1 position 1 and TB1 posi-
tion 2, 3, or 4.
13. On TB1 and TB2, disconnect all wires coming
from the ACPW
.4/
and note their position.
14. If you are exchanging the transformer of the
basic ACPW, unplug connectors J11 and J12
from the rear of the DCDP.
For the backup ACPW, unplug connectors J9
and J10 from the rear of the DCDP.
15. Remove the screw holding the ACPW.
.5/
16. Disconnect the two ground straps coming from
the ACPW.
.6/
17. At the front of the machine, remove the two
screws holding the power box. Slide the
ACPW out.
Note
When you remove the basic ACPW, if the
backup ACPW is installed, you have to
remove the bracket.
.7/
18. Unscrew the two screws which secure the
transformer to the frame.
19. At the rear of the machine, disconnect the two
ground wires from the transformer.
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3746-900: Service Guide