[B] Before Checking Controller Board - Hoshizaki IM-21 Service Manual

[b] BEFORE CHECKING CONTROLLER BOARD

Check the power source voltage and the components as shown in the table below.
Component
1. Actuator Toggle
Switch
COM.
DEFROST FREEZE
2. Thermistor
(on Evaporator)
Holder
Screw
Evaporator
Thermistor
3. Bin Control Switch
Manually set the switch in the FREEZE
and DEFROST positions, and check the
continuity.
N.O.
N.C.
Thermistor Sensor part is fragile,
glass sealed. Handle with care.
* Disconnect the Connector K4 on the
board.
* Remove the screw and the Thermistor
Holder on the Evaporator.
* Immerse the Sensor part in a glass
containing ice and water for 5 minutes.
* Check the resistance between K4
Connector Pins.
* Replace the Thermistor in its correct
position.
* Connect K4.
Manually set the Micro Switch in the
TRIP and RESET positions, and check
the period.
Procedure
CAUTION
28
Normal
DEFROST
COM-NO Open
COM-NC Closed
FREEZE
COM-NO Closed
COM-NC Open
5 -7 kilohms
Approx.
TRIP(Closed) 10 sec.
RESET(Open) 80 sec.