Circuit Board Diagrams - Mitsubishi Electric LGH-F300RVX2-E Handbook

6. Circuit board diagrams

Circuit board diagrams and check points
(1) Control circuit board
Caution:
Before servicing (including replacing the circuit boards), be sure to turn off the power supply isolator
and check that all the LEDs on the control circuit board and power circuit board are not lit. A large-
capacity electrolytic capacitor on the circuit board may carry voltage for several minutes after the iso-
lator is turned off.
CN105: For optional components
IT communication transmission cable
CN26: For optional components
CO
2
0–10 V DC signal input
External bypass switching input
TM3
Monitor output
Output ON: 0 Ω
∞
Output OFF: Ω
TM4
Remote controller
transmission cable
11 to 14 V DC
TB5
M-NET transmission cable
M-NET transmission cable
A B
24 to 30 V DC
(When using M-NET)
Shielded wire
S
TM2
External control input
Voltage-applied signal
1 2
Volt-free contact signal
Y Z
13 V DC
(Insulated)
Power for the circuit
GND
(Insulated)
Power for the circuit
CN19, CN14
Power circuit board
connection
CN13, CN21
Power circuit board
connection [2]
(*Note 1)
*Note 1:
The connection is available only for the following models.
LGH-F940RVX2-E, LGH-F1200RVX2-E
sensor signal input
Lot number indication
CN34: For optional components
CO sensor display output
2
CN35: For optional components
CO sensor error input
2
CN50: For optional components
External monitor output device
CN17
External control input
Fan speed switching
Circuit board name
CN23: For optional components
CO sensor power supply output
2
CO sensor
2
power supply indicator
(LED5 Green)
CN7
Outdoor air (OA) thermistor
CN5
Return air (RA) thermistor
─ 11 ─
CN32
Remote/Local switching input
CN12: For rewriting the
microcomputer software
Remote controller
power supply indicator
(LED3 Green)
Fed with power: lit
Not fed with power: unlit
Power supply indicator
for the circuit board
(LED4 Red)
Fed with power: lit
Not fed with power: unlit
Error indicator
(LED1 Green)
Normal: unlit
Error: blinking
During delay operation: lit
M-NET indicator
(LED2 Red)
Registered: unlit
Not registered: lit
M-NET communication error: blinking
Address setting switch
SW12
(tens digit)
Address setting switch
SW11
(ones digit)
Indication of the microcomputer
software No.
CN38: For rewriting the
microcomputer software
SW2
Function selection switch
SW5
Model selection switch
SW6