Teledyne 1220 - Multipoint flammable gas and vapor detection system - Manual (Page 23)

3-5
Multi-Channel Combustible Monitor Installation 3
Teledyne Analytical Instruments
3.3 Control Unit
In the event that it becomes necessary to remove the Control Unit,
primary power to the System Chassis must first be disconnected, and the six
small screws around the periphery of the Control Unit front panel removed.
The two knurled, slotted jack screws may then be backed out to pull the
Control Unit out until it is disengaged from its socket. It may then be slid out
of the chassis.
Reinstallation of the Control Unit simply requires that it be slid into the
system chassis, making certain that the circuit board lines up with the con-
nector. The circuit may be seated in the connector by tightening the jack
screws. The six retaining screws may then be reinstalled and the primary
power reconnected to the System Chassis.
Do not hotswap (remove or install with power on) the chan-
nel modules to system chassis. Failure may occur by causing
power shorts while lining up the circuit board with the
backpanel connector.
Install channel modules starting at the end of the system
chassis, working toward the middle to prevent missalignment
problems.
3.3.1 Control Unit Fuses
The Control Unit contains three fuses. Two 3 Amp fuses protect the
entire system (one fuse for Hot, one for Neutral). An independent 1/8 Amp
fuse protects the Control Unit circuitry. To change any of the fuses, twist the
fuse holder knob counterclockwise and slide the holder out until the fuse is
visible, install the new fuse, slide the holder back in, and turn the knob
clockwise.
3.3.2 Control Unit Jumper Settings
The Control Unit may be configured by changing the installation of the
jumpers on the PCB. See the following sections for complete jumper instal-
lation information. The default jumper installation is: