Mitsubishi Electric MUY-GL09NA-U1, Service Manual

Page: 58 / 76

58
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press EMERGENCY OPERATION
switch.
A
Is serial signal
error indicated 6
minutes later?
B
Yes
• Reinstall
either the unit
or the light
away from
each other.
• Attach a filter
on remote
control receiv-
ing section
of the indoor
unit.
No
Turn OFF the power supply.
Is there rated voltage in the power supply?
Yes
No
Turn ON the power supply.
Check the power supply.
Is there rated voltage between outdoor terminal block S1 and S2?
No
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the OPERATION INDICATOR lamp light
up? <Confirmation of the power to the indoor
unit>
Yes
No
Is serial signal error indicated 6 minutes
later?
Yes
No
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor connect-
ing wire?
Yes Correct them.
No
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3. 1
B
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confirm the wiring is correct before the opera -
tion starts.
Turn ON the power supply.
Does the LED on the inverter P.C. board or the outdoor electronic control P.C.
board repeat "3.6-second-OFF and 0.8-second-ON quick blinking"? 3
Yes
GL24 GL18
No
(Lit or
not lit)
Replace the inverter P.C. board or the outdoor
electronic control P.C. board. 2
2. Be careful of the residual voltage of smoothing
capacitor.
Turn OFF the power supply.
Remove the bridge between outdoor terminal block S2 and S3.
Yes
3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board or the outdoor electronic control P.C.
board is normal, LED blinks 6 times after 3 minutes.
(Except for outdoor unit of multi system type)
Is the bus-bar voltage of the inverter P.C. board or the outdoor electronic control P.C. board normal? (Refer
to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.) No
Yes
Replace the indoor electronic control P.C. board. Turn on the power supply.
Is there amplitude of 10 to 20 V DC between the indoor terminal block
S2 and S3? <Confirmation of serial signal>
Yes
Is there 2 V DC or less between CN10A (+)
and GND (-) on the indoor electronic control
P.C. board?
No Yes
Is there 2 V DC or less between
CN10A (+) and GND (-) on
the indoor electronic control P.C.
board?
Is there 2 V DC or less between
CN10A (+) and GND (-) on
the indoor electronic control P.C.
board?
Replace the indoor elec-
tronic control P.C. board.
No Yes No
Yes
No
Replace the indoor power
P.C. board.
MUZ-GL18/24NA
MUZ-GL18/24NAH
MUY-GL18/24NA
OBH733G