Thetford NR740 - Manual (Page 5)

Refrigerator Service Manual 5 DC0040(K), DC0051(K), DE0040, DE0051, DE0240T, DE0251T,
DC0740(X), DE0740(X), DC0751(X), DE0751(X) Models
Troubleshooting - Procedure C
Power Supply Output Voltage
Change DC
Power Supply
Change DC
Power Supply
Change DC
Power Supply
Change DC
Power Supply
Change DC
Power Supply
Change DC
Power Supply
DC Power
Supply Failure
DC Power
Supply Failure
DC Power
Supply Failure
DC Power
Supply Failure
Check AC Power
Supply.
(37 - 45V DC)
(See Figure 5)
Check AC Power
Supply.
(37 - 45V DC)
(See Figure 5)
Power
Source
Less than
15V AC
15 - 25V
AC
Measure Voltage
Between A & B
At the Compressor
(See Figure 4)
Go to
Procedure E
Change
Thermistor
Normal
See
Procedure D
0V AC
DC
OPERATION
AC
OPERATION
GOOD
GOOD
BAD
BAD
DC
AC
GOOD
THERMISTOR
FAULTY
THERMISTOR
Note: Measurements taken with 12.8V DC or 120V AC power supply.
AR
T01948
A
B
AR
T01949
Figure 4. Measuring Power Supply Output Voltage
AR
T01950
Figure 5. Measuring AC Power Supply Output
Power Supply Output Voltage