Mitsubishi Electric CMB-WP1016V-GA1 Service Handbook page 176

[ VIII Troubleshooting ]
(2) Judgment methods and possible failure mode
Malfunction
mode
Microcomputer
driver circuit fail-
ure
LEV mechanism
is locked
Disconnected or
short-circuited
LEV motor coil
Faulty wire con-
nections in the
connector or
faulty contact
HWE1410A
Judgment method
Disconnect the control board connector and connect
the check LED as shown in the figure below.
LED
1 k
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.
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.
Measure resistance between the coils (red - white, red
-orange, brown - yellow, brown - blue) using a tester.
They are normal if resistance is 150ohm
1. Check for loose pins on the connector and check
the colors of the lead wires visually
2. Disconnect the control board's connector and
conduct a continuity check using a tester.
When the drive circuit has a
problem, replace the control
board.
6
5
4
3
2
1
Replace the LEV.
Replace the LEV coils.
10%.
Check the continuity at the
points where an error occurs.
- 167 -
Remedy
GB