
2. HARDWARE
B–63445EN/01
62
1 Make sure that the power supply unit is turned off.
2 Disconnect all cables connected to the control unit. Pinch the 20–pin
half–pitch connector to release the latch. Draw out the connector.
3 Remove the control unit from the wall.
4 Place the control unit with its left face upward, and press the two
points shown in Fig. 2.8.1 (a) to remove the cover of the case.
5 Remove the battery.
6 Release the three latches shown in Fig. 2.8.1 (b), and remove the base
PC board.
7 Mount a new base PC board by following the steps above in reverse
order.
8 Reconnect the cables to their original positions.
CAUTION
Replacing the base printed circuit board results in the loss
of stored data such as programs and parameters. Before
attempting to replace the memory module, therefore, make
a backup copy of the stored data.
2.8
REPLACING
PRINTED CIRCUIT
BOARD AND UNIT
2.8.1
The Base Printed
Circuit Boards