Mitsubishi Electric CAHV-P500YB-HPB, Service Handbook

Page: 142 / 169

[
IX
Troubleshooting ]
- 135 -
HWE15070 GB
(1) 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.
Pulse signal is output for 17 seconds when the main
power is turned on.
If there is any LED that remains unlit or remains lit,
there is a problem with the drive circuit.
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.
Measure resistance between the coils (red - white, red
-orange, brown - yellow, brown - blue) using a tester.
They are normal if resistance is 46ohm 3%.
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
resistance
LED
resistance:0.25W 1k Ω
LED:15VDC 20mA more
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