Thetford NR740 - Manual (Page 10)

DC0040(K), DC0051(K), DE0040, DE0051, DE0240T, DE0251T,
DC0740(X), DE0740(X), DC0751(X), DE0751(X) Models
Refrigerator Service Manual 10
Troubleshooting - Quick Reference
Quick Reference Troubleshooting Steps
Check for supply voltage at the rear of the refrigerator. 1.
Turn the temperature control to the "On" position. 2.
The operating voltage should be between 10.5V and
32V DC. There will be some variation in these readings
depending on the supply voltage.
Check the compressor voltage between points A and B.
3.
Voltage should be between 15V - 25V AC. Refer to Figure
10.
If voltage is not within range, refer to Procedure C.
With the refrigerator power on, take an Ohm reading (1.4
4.
- 3.5Ω) at the compressor between points A and B. Refer
to Figure 11.
If the Ohm reading is not within range, refer to Procedure
B.
With the refrigerator power off, and the lead removed
5.
from point "A", take an Amp reading (1.6 - 3.3 Amps) at
the black wire with the rubber boot. Refer to Figure 12. If
amperage is not within range, refer to Procedure D.
A
B
AR
T01949
Figure 10. Checking Compressor Voltage
AR
T01958
B A
Figure 11. Taking an Ohm Reading
A
AR
T01953
Figure 12. Measuring the Amp Draw