IBM FlashSystem 900, Service Manual

Page: 477 / 546

FRU Exchange
Exchange an ACPW
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
When the basic ACPW is disconnected, the
3746-900 power ON is no longer possible
even if the backup ACPW/DCPW is con-
nected.
1. Locate the ACPW that you have to exchange
using Figure 4-9 on page 4-8.
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 5.
If not, proceed with the next step.
4. The machine has its Ready LED ON and
does not have another ACPW or DCPW.
a. Press the 'standby' key on the control
panel to put the machine in standby
mode.
b. Go to step 7.
5. There is another ACPW or DCPW in your
3746-900.
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 dropping
and stop the power monitoring.
7. If not already done, switch the main circuit
breaker CB1 OFF, on the ACPW that you
exchange.
.2/
8. Unplug the J1 connector from that 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 that you want to remove.
.3/
12. Check that on the transformer there is no
voltage between TB1 position 1 and TB1 posi-
tions 2, 3, or 4.
13. On TB1 and TB2 disconnect all wires coming
from the ACPW
.4/
and note their position.
14. If you exchange the basic ACPW, unplug con-
nectors J11 and J12 from the rear of the
DCDP.
Or 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/
TB1 Position Voltage
1
2 200 V
3 220 V
4 240 V
Chapter 4. 3746-900 FRU Exchange
4-11