Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual

Page: 222 / 301

[
IX
Troubleshooting ]
- 213 - HWE1113B GB
(2) Judgment methods and possible failure mode
Malfunction
mode
Judgment method Remedy
Microcomputer
driver circuit fail-
ure Disconnect the control board connector and connect
the check LED as shown in the figure below.
resistance : 0.25W 1k
LED : DC15V 20mA or more
When the main power is turned on, the indoor unit cir-
cuit board outputs pulse signals to the indoor unit LEV
for 10 seconds.
If any of the LED remains lit or unlit, the drive circuit is
faulty.
When the drive circuit has a
problem, replace the control
board.
LEV mechanism
is locked If the LEV is locked, the drive motor runs idle, and
makes a small clicking sound.
When the valve makes a closing and opening sound,
the valve has a problem. Replace the LEV.
Disconnected or
short-circuited
LEV motor coil Measure resistance between the coils (red - white, red
-orange, brown - yellow, brown - blue) using a tester.
They are normal if resistance is 150ohm
10%.
Replace the LEV coils.
Faulty wire con-
nections in the
connector or
faulty contact 1. Check for loose pins on the connector and check
the colors of the lead wires visually Check the continuity at the
points where an error occurs.
2. Disconnect the control board's connector and
conduct a continuity check using a tester.
6
5
4
3
2
1
1 k LED