Mitsubishi PWFY-P36NMU-E-BU Service Handbook page 61

. Phenomena
hen the remote controller operation S is turned on, the operation status briefly appears on the display, then it
goes off, and the display lights out immediately, and the unit stops.
2. Cause
1) The power for the M-NET transmission line is not supplied from the outdoor unit.
2) Short circuit of the transmission line.
3) Incorrect wiring of the M-NETtransmission line on the outdoorunit.
Disconnected wire for the MA remote controller or disconnected line to the terminal block.
The male power supply connectors on the multiple outdoor units are connected to the female power supply switch
connector (CN40).
In the system to which the power supply unit for transmission lines is connected, the male power supply connector is
connected to the female power supply switch connector (CN40) on the outdoor unit.
4) Broken M-NET transmission line on the unit side
5) Faulty wiring or loose connector between the terminal block for M-NET transmission line connection (TB5) on the
unit and CM2M on the indoor unit circuit board
3. Check method and remedy
1)
When 2) and 3) above apply, check code 7 02 will be displayed on the self-diagnosis LED.
Same symptom for al l uni t s i n a
system wi t h one outdoor uni t ?
Check the
self-diagnosis LED
Is the error code 7102
di s pl a yed?
Check 1).
NO
YES
YES
Checkfor
2and3.
NO
Check 4.
Correct
the error.
Correct the error.
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Measure the voltages at the terminal
block for transmission line connection
(TB5) on the unit.
NO
17 - 30V?
YES
Check 5.
YES
Error found?
NO
Circuit board fault or MA
remote controller error