Mitsubishi Electric PURY-P200 Service Handbook page 191

(2) Outdoor unit transmission power source circuit failure judgment
Check voltage of indoor/outdoor transmis-
sion terminal block (TB3) of outdoor unit.
DC24 ~ 30V
NO
Check voltage of TB3 by removing
transmission line from TB3.
DC24 ~ 30V
NO
Check whether power supply connector is
replaced with CN40.
NO
Replaced
YES
Check voltage of terminal block for
centralized control (TB7).
DC24 ~ 30V
NO
Check voltage of TB7 by removing
transmission line from TB7.
DC24 ~ 30V
NO
Check voltage between 1 and 2, and 1 and 3
of main board CNVCC1
DC24 ~ 30V
NO
Check voltage between 1 and 2, and 1 and 3
of main board CNVCC1
DC24 ~ 30V
NO
Check connector (CNL1 and CNL2) on filter
board for pulling off.
Connector being pulled off?
NO
Check voltage between 1 and 3 of INV
board CNDC2.
DC517 ~ 587V
NO
Check voltage of outdoor unit power
source terminal block TB1.
AC342 ~ 457V
YES
Check connector on outdoor unit board for pulling off.
INV board : CNDC2
G/A board : CNDC1
NO
Connector being pulled off?
NO
Check wiring inside outdoor unit.
G/A board : CNDC1 – INV board : CND2
Faulty wiring?
NO
Check fuse (F02) on INV board.
Damaged?
NO
Check rush current protection resistance.
42 ~ 52Ω
YES
Check diode stack.
Broken?
NO
YES
Check and modify transmission line for
disconnection & poor contact
YES
Check and modify indoor/outdoor
transmission line for short circuit.
YES
Check wiring between connectors (CNS1 and TB3).
Check pulling off of connector (CNS1).
YES
Connector being Connector being
Modify pulling off of connector.
pulled off? pulled off?
NO
YES
Check and modify shorting of trans-
mission line for centralized control.
YES
Replace main board.
YES Check and modify wiring between main board
connector (CNVCC1) and INV board connector
(CNVCC1).
YES
Modify pulling off of connector.
YES
Replace INV board.
NO
Confirm and modify power source
wiring and main power source.
YES
Modify pulling off of connector.
YES
Modify wiring.
YES
Replace fuse.
NO
Replace rush current protection resistor.
YES
Replace diode stack.
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Apply power source again.