March 2021
Page 122 of 143
59812-K007 Rev 17
Business Confidential
Figure 186
Control Unit Terminal Blocks
7.
Disconnect the detector connectors (1 through to 10) There is a push bar at the side of the
connector to release it, taking care not to damage the connection wires or the connector
pins/connections.
8.
Remove the 4 screws at the corners of the Control Unit PCB.
9.
Do NOT remove the 2 screws in the middle of the PCB as this will loosen the center standoffs. The
replacement PCB will already have the middle screws and standoffs fitted.
10.
Remove the PCB.
11.
Fit the replacement PCB in reverse order to the above, ensuring stand-offs are in place and the
ground wire is secure under the bottom left PCB screw, contacting the PCB.
12.
Ensure the terminal block connections and detector connections are securely re-made and Modbus
end of line jumper links are in the correct positions.
13.
After replacing the PCB power up the unit and check that the correct number of detectors are
indicated.
14.
If required set the correct Modbus address, see section 2.10
In the case of Control Units without a membrane fitted an approved service engineer will be required
to change the Modbus address.