mabe PSS21 Series, Service Manual

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Dispenser Board
There is no self-diagnostic test for the dispenser board. The operation of the dispenser board is tested by
pressing each button and checking its proper operation.
Self-Test Sensor and Control System (0 7)
This test checks all five thermistors located through the unit. Once the test is started, the test code (0 7) will
stop flashing and the thermistor test results will appear on the freezer screen in the test order listed below.
The sequence number of the thermistor test will not be shown on the screen.
If the unit is not equipped with the Quick Cool option, the third thermistor (rapid cooling) will show 0 and three
audible beeps will sound on the temperature control panel. This is not a fault if the unit is not equipped with
the option of Fast Cooling.
Thermistor test results:
P = Pass
0 = Fail
S = Short to 5 VDC
B = Bad amplifier
The sequence of the thermistor test is:
1. Top cooler thermistor
2. Lower cooler thermistor
3. Quick cooling thermistor (0 displayed if the unit is not equipped with the Quick Cool option)
4. Evaporator thermistor.
5. Freezer thermistor.
Note: The results of the thermistor test will appear in the sequence shown above. The number of the
thermistor test sequence will not be shown on the screen.