5-6
Integrated Remote Monitor Unit
Electrical Maintenance
CSR-20 & CSR-40, September 1999
2.
Check for the RXD signal at the IRMU; see Step 2 call-
out on diagram.
a.
If signal is present, check the connections; repair or
replace IRMU if necessary.
b.
If signal is not present; go to step 3.
3.
Check the harness wires between the IRMU board and the
power module board for shorts and continuity. Check the
harness wires between the power module board and the
µ
P-D controller for shorts and continuity.
a.
If a harness is defective, replace the harness.
b.
If both harnesses are OK, check the controller using
the Microprocessor Tester.
c.
If the controller is OK, replace the power module
board.
NOTE: If the remote computer is unable to obtain
data from a unit and the operator determines the
remote monitoring unit is faulty, the complete
remote monitoring unit circuit board must be
replaced. No other repair is possible.
Remote Monitor Unit Replacement
1.
Disconnect 46O/380V power supply to the unit.
2.
Remove the circuit board’s 460/380V power leads from
the high voltage terminal strip in the remote monitor unit
box.
3.
Disconnect the circuit board’s six leads for serial data
communication at bottom of enclosure.
4.
Remove the two nuts that mount the circuit board’s alu-
minum mounting tray in the remote monitor unit box.
5.
Remove the circuit board and aluminum mounting tray
assembly from the unit.
6.
Place a new circuit board assembly in the unit and install
the mounting screws.
7.
Connect six wires for serial data communication.
8.
Connect the circuit board 460/380 V power leads on the
high voltage terminal strip.
9.
Reconnect 460/380V power supply to the unit.
Problem 3: RMU Unit Section Diagram
