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P
AGE
33
5.
Disconnect the ribbon cables to the power supply and CPU boards
if necessary for easier access.
6.
Pull the subassembly out of its connectors.
7.
Disconnect the ribbon cable.
8.
On the replacement subassembly, make a Z-fold in the ribbon cable
similar to the other cables already in the unit.
9.
Connect the ribbon cable.
10.
Install the subassembly board.
11.
Reconnect the ribbon cables to the power supply and CPU boards if
they were disconnected.
12.
Reinstall the fuse.
WARNING:
Do not reconnect the power connector at TB1 with the fuse
installed. This may damage the unit. Reinstall the power
connector at TB1 first, then reinstall the fuse.
13.
Push the power supply and CPU boards into place.
14.
Close the unit.
15.
Verify proper operation of alarms by the replacement subassembly.
C
ONTROL
I
NTERFACE
S
UBASSEMBLY
To replace a subassembly:
1.
Open the unit (refer to Fig. 23).
2.
Pull the power supply and CPU boards down from the other cir-
cuitry (refer to Fig. 24).
3.
Remove power by pulling out the fuse. The power connector at TB1
does not need to be disconnected.
4.
Refer to Fig. 26 for the location of the Control Interface subassem-
blies.
5.
Disconnect the ribbon cables to power supply and CPU boards.
6.
Remove the three screws from the bottom of the unit (refer to
Fig. 27).
SUBASSEMBLY REPLACEMENT
CONTINUED
. . .
