[E] Checking The Controller Board - Hoshizaki KMD-900MRH Service Manual

[e] Checking the Controller Board

1) Visually check the sequence with the icemaker operating.
2) Visually check the controller board by using the following procedures.
(i) Adjust the defrost timer to minimum position.
Disconnect the thermistor from the controller board.
Connect a 1.5 kΩ - 3.5 kΩ resistor to the connector K3 (pins #1 and #2), and energize
the unit.
After the 1 minute ± 5 second water supply cycle and the 2 minute ± 10 second defrost
cycle, the unit should start the freeze cycle.
(ii) After the above step (i), disconnect the float switch leads from the controller board within
the first 5 minutes of the freeze cycle.
The unit should go into the defrost cycle after the first 5 minutes ± 20 seconds of the
freeze cycle.
(iii) Reconnect the float switch connector to the controller board. After the first 5 minutes
of the freeze cycle, disconnect the float switch leads from the controller board.
At this point, the unit should start the defrost cycle.
(iv) After step (iii), de-energize the unit and confirm that the defrost timer is in the
minimum position. Disconnect the resistor from the controller board, and energize
the unit.
After the 1 minute water supply cycle, the defrost cycle starts.
Reconnect a 1.5 kΩ - 3.5 kΩ resistor to the connector K3 (pins #1 and #2) after the
first 2 minutes of the defrost cycle.
The unit should start the freeze cycle after 1 minute ± 5 seconds from the resistor
connection.
3) Check the controller board by using test program of the controller board.
The output test switch "S3" provides a relay sequence test. With power OFF, place S3
on and switch power to ICE. The correct lighting sequence should be none, 2, 3, 4, 1,
and 4, normal sequence every 5 seconds. S3 should remain in the "OFF" position for
normal operation.
30