Toshiba MMY-MUP0961HT6P-UL Service Manual page 195

Points to Note When Servicing Compressor
(1) When checking the outputs of inverters, remove the wiring from all the compressors.
How to Check Inverter Output
(1) Turn off the power supply.
(2) Remove compressor leads from the compressor P.C. board.
(The model with two compressor should remove the wiring for two sets (6 leads).
(3) Turn on the power supply and start cooling or heating operation.
(4) Check the output voltage across each pair of inverter-side. If the result is unsatisfactory according to the
judgment criteria given in the table below, replace the compressor P.C. board.
No. Measured leads
1 CN201 - CN202
2 CN202 - CN203
3 CN203 - CN201
How to Check Resistance of Compressor Winding
(1) Turn off the power supply.
(2) Remove compressor leads from the compressor P.C. board. (Be sure to remove all the leads.)
(3) With each compressor, check the phase-to-phase winding resistances and winding-to-outdoor cabinet
resistance using a multimeter.
• Earth trouble?
It is normal if the winding-to-outdoor cabinet resistance is 10M
• Inter-winding short circuit?
Normal resistance between phase to phase is below. (Use a m multimeter)
• LA771A3TB-20M : 0.242 ± 0.012Ω
• LA1201K4FB-10UC : 0.204Ω ± 0.01Ω
How to Check Outdoor Fan Motor
(1) Turn off the power supply.
(2) Remove fan motor leads from the fan P.C. board for the outdoor fan.
(3) Rotate the fan by hand. If the fan does not turn, the fan motor is troubled (locked up). Replace the fan motor.
If the fan turns, measure the phase-to-phase winding resistances using a multimeter. It is normal if the
measurements are in the 9.3-11.5
Criterion
240-400V
240-400V
240-400V
W : BLACK lead wire(CN203)
V : WHITE lead wire(CN202)
U : RED lead wire(CN201)
range. (Use a digital multimeter.)
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or more.
Ω