Mitsubishi Electric CITY MULTI PUHY-P200YEM-A Service Handbook page 96

[2] Trouble and remedy of remote controller
(In the case of MA remote controller)
Phenomena
1 If pushing the remote
control operation SW
does not make a
sound such as feep
with the crystal
display lamp out, and
no operate is
possible.
(An appropriate
display on the
remote control is not
on.)
2 When turning on the
remote control
operation SW, a
temporary operation
display is indicated,
and the display lights
out immediately, the
unit stops.
Factors
1) Power supply from transformers is not turned on in
Indoor Unit.
1 The original power supply of Indoor Unit is not
turned on.
2 The connector (CND. CNT, CN3T) on the
controller board in the room has come off.
3 Fuse on the control board in Indoor Unit has melting down.
Transformer defects or damage to unit.
2) MA remote controller has been wired incorrectly.
1 Break of the MA remote controller line and the
connection to the terminals has come off.
2 Short circuit of the MA remote control wiring
3 Reversed connections of the wiring on remote
controller.
4 Incorrect connection of the MA remote control wiring
to the transmission line terminal block (TB 5).
5 Reversed connections between the MA remote
control wiring in the indoor unit and AC 200V
power supply wiring.
6 Reversed connection between the MA remote
control wiring in the indoor unit and M-NET
transmission wiring.
3) The maximum number of MA remote controllers
connected to one is unit exceeded (two units).
4) The wiring length of the MA remote line and the
used electric wire diameter is out of specifications.
5) The wiring of the remote display output to the
outdoor unit is short circuited, or the relay is
connected with reversed polarity.
6) Defective of the controller board in the room
7) Defects of MA remote control
1) M-NET transmission power supply from the outdoor unit is not
supplied.
1 The original power supply of the outdoor unit is not turned on.
2 Disconnection of connectors on the board of the outdoor unit.
Main board --- CNS1, CNVCC3
INV board --- CNAC2, CNVCC1, CNL2
3 Power supply circuit defects of the outdoor unit.
(For detail, refer to Pages 127)
• INV board defects
• Blown fuse (F1 on INV Board)
• Diode stack destruction
• Prevention resistance of rush current (R1) damage
2) Transmission line short
3) Wiring mistakes of the M-NET transmission line on the side of
the outdoor unit
1 Break of transmission line, and removal of terminal block
2 The room transmission line is wired to the transmission line
terminal block (TB7) for the central control by mistakes.
4) M-NET transmission line break on the side of the room unit
5) Disconnection off wiring between the M-NET transmission terminal block
(TB 5) and the room controller board CN2M and pulls off of connectors
a) Check the MA remote control terminal
b) Remove the remote control wiring from
- 95 -
Check method and handling
voltage (between A and B).
i) In the case of voltage DC8.5- 12V,
the remote controller is defective.
ii) In the case of voltage not available:
• Check the left described 1) and 3),
after checking , if these are factors,
then modifications should be
performed.
• If there are no factors of the left
described 1) and 3), move to b).
the terminal block TB13 for the MA
remote control in the indoor unit, and
check voltage between A and B.
i) In the case of voltage DC9-12V
Check the left described 2) and 4), if
these are factors, then modifications
should be performed.
ii) In the case of voltage not available:
• Recheck the left described 1) once
again, if this is a factor, them
modifications should be performed.
• If there are no factors in the left
described 1), check the wiring for the
remote display (the relay polarity, etc.)
• If there are no factors, replace the
controller board in the indoor unit.
In the case of item 1), the
LED 1 on the controller
board in the unit is off.
In the case of factors 2) and
3) Indicated by 7102 error
code on the self-diagnosis
LED of the outdoor unit.