Hoshizaki Modular Cubelet Serenity Series Service Manual page 15

2. Diagnostic Procedure
This diagnostic procedure is a sequence check that allows you to diagnose the electrical
system and components. Before proceeding, check for correct installation, proper voltage
per appliance nameplate, and adequate water pressure (10 PSIG to 113 PSIG). Check
that both the 24VAC circuit fuse and the 115VAC GM fuse are good.
Note: • When checking high voltage (115VAC), always choose a neutral (W) wire to
establish a good neutral connection.
• When checking low voltage (24VAC), always choose a neutral (LBU) wire to
establish a good neutral connection.
• When checking control board DC voltage (5VDC), always place the red positive
test lead from the multimeter to CB K5 pin closest to CB K4 connector.
See "II.C. Control Board Check."
• When checking BC1 (infrared sensor) (20VDC), check that BC1 (infrared sensor)
green LED is on. This green LED confirms 20VDC power from CB K6 to BC1
(infrared sensor) and remains on constantly. If green LED is not on, check for
20VDC from CB K6 #1 (DBU) to CB K6 #3 (BR). See "II.D. Bin Control Check."
• To speed up the diagnostic process, the 5-min. ice purge cycle may be bypassed
by pressing the "SERVICE" button on the control board after the gear motor
starts. WARNING! Risk of electric shock. Care should be taken not to touch
live terminals.
• If the icemaker is in alarm, see "III.A.2. LED Lights and Audible Alarm Safeties."
• EH energizes when "GM" LED turns on.
• CB X1 relay energizes PDS. After PDS energizes, CPLS closes, then MC
energizes, energizing Comp and FMR.
• CB monitors the following switches with 5VDC during the icemaking process:
Control Switch (CS), Compressor Control Relay (CCR), Float Switch (FS). When
5VDC is present across any of these switches, the switch is open.
1) Remove the front panel, then move the power switch to the "OFF" position. Move the
control switch to the "DRAIN" position, then move the power switch back to the "ON"
position. Replace the front panel in its correct position.
2) Allow the water system to drain completely.
3) Remove the front panel. Move the power switch to the "OFF" position, then unplug the
appliance from the electrical outlet.
4) Remove the control box cover and access CB.
5) Check the CB S1 dip switch settings, see "III.B.1. Default Dip Switch Settings" to assure
that they are in the correct positions. For proper operation of BC1 (infrared sensor),
confirm that S1 dip switch 7 is in the "ON" position.
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