GE PSC21MGM, Technical Service Manual

Page: 34 / 76

– 32 –
Diagnostics
Table of Contents
Efficient Use of Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Failure Causes (Table 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Self Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Diagnostic Tests (Table 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Communication Tests (0 2, 0 3, or 0 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Temperature Control Panel Self-Test (0 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Dispenser Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Control and Sensor System Self-Test (0 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Main Control Board (Low-Voltage Side) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Main Control Board (120-VAC Side) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Main Control Board Locator Table (Low-Voltage Side) . . . . . . . . . . . . . . . . . . . 39
Main Control Board Locator Table (120-VAC Side) . . . . . . . . . . . . . . . . . . . . . . 40
Unit Dead, No Sound & No Cooling (diagnostic chart) . . . . . . . . . . . . . . . . . . . 42
Fresh Food Warm - Freezer Warm (diagnostic chart) . . . . . . . . . . . . . . . . . . . . 43
Fresh Food Warm - Freezer Normal (diagnostic chart) . . . . . . . . . . . . . . . . . . . 44
Fresh Food Too Cold - Freezer Normal (diagnostic chart) . . . . . . . . . . . . . . . . 45
Freezer Warm - Fresh Food Normal (diagnostic chart) . . . . . . . . . . . . . . . . . . . 46
Compressor Not Running (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Damper Door Not Opening or Not Closing (diagnostic chart) . . . . . . . . . . . . . 48
Condenser Fan Not Running (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . 49
Evaporator Fan Not Running (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . 50
Fresh Food Fan Not Running (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . 51
Heavy Frost on Evaporator (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Thermistor Test (diagnostic chart) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Thermistor Values (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Efficient Use of Diagnostics
For the most efficient use of the diagnostics, find the appropriate diagnostic chart and proceed as
directed in the chart. When directed to enter Self Diagnostics, refer to the Self Diagnostics section of
this chapter for more information. When directed to perform a diagnostic test (example; encoder test 0
5), refer to Table 2, Diagnostic Key Sequences, for more information.