Mitsubishi Electric MUZ-FH06NA, Service Manual

Page: 45 / 58

45
M How to check miswiring and serial signal error
NOTE:
Refer to the indoor unit service manual.
• 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 fi lter
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 the outdoor terminal block S1 and S2?
No
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICATOR
lamp light up? <Con
fi rmation 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 con
fi rm the wiring is correct before the opera-
tion starts.
Turn ON the power supply.
Does the LED on the inverter P.C. board repeat
"3.6-second-OFF and 0.8-second-ON quick blinking"? 3
Yes
No
(Lighted
or not
lighted)
Replace the inverter P.C. board . 2
2. Be careful of the residual voltage of
smoothing capacitor.
Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Con fi rmation of serial signal>
Yes
Check the wiring
If there are any error of the indoor/outdoor connecting wire:
such as the damage of the wire, intermediate connection,
and/or poor contact to the terminal block, replace the indoor/
outdoor connecting wire.
No
Is there 2 VDC or less between CN202 (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?
No
Yes
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 is normal, LED blinks 6 times after 3
minutes.
Is there 2 VDC or less between
CN202 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
Is there 2 VDC or less between
CN202A (+) and JPG (GND)(-)
on the indoor electronic control P.C.
board?
Replace the indoor elec-
tronic control P.C. board.
No Yes No
Yes
Is the bus-bar voltage of the inverter P.C. board normal?
(Refer to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.)
No
Yes
Check of power supply.
(Refer to the outdoor
service manual.)
Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Turn ON the power supply.
Yes
No
Replace the indoor power
P.C. board.
Is there rated voltage between the indoor terminal block S1 and S2?
<Con fi rmation of power voltage>
OBH684C