Service Diagnosis - Hoshizaki KM-301BAJ Service Manual

B. Service Diagnosis
• The appliance should be diagnosed and repaired only by qualified service
personnel to reduce the risk of death, electric shock, serious injury, or fire.
• Risk of electric shock. Control switch in "OFF" position does not de-energize all
loads Use extreme caution and exercise safe electrical practices.
• Moving parts (e.g., fan blade) can crush and cut. Keep hands clear.
• CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are
securely in place after the appliance is serviced. Make sure that none have fallen
into the dispenser unit/ice storage bin.
• Make sure all food zones in the appliance and dispenser unit/ice storage bin are
clean after service.
The 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 nameplate, and adequate water supply. Check CB using the steps in "II.C. Control
Board Check." Check dip switch settings to assure that S1 dip switches 3, 4, 7, 8, 9, & 10
and S2 dip switches 1 through 6 are in the factory default position. S1 dip switch
1, 2, 5, and 6 are cleaning adjustments and the settings are flexible. For factory default
settings, see "III.C.1. Default Dip Switch Settings."
Note: When checking high voltage (115VAC), always choose a white (W) neutral wire to
establish a good neutral connection.
1) Remove the louver. Move the control switch to the "OFF" position, then unplug the
appliance from the electrical outlet. Clear any ice from BC.
1. Sequence and Component Diagnosis
3) Power On: Plug the appliance into the electrical outlet. Move the control switch to the
"ICE" position. Check that the 5A 250V fuse is good. A 5-sec. delay occurs.
CB red "POWER OK" LED turns on.
Note: • CB red "POWER OK" LED remains on unless the 10.5VAC power supply is
interrupted (K2 connector).
• Check CB using the steps in "II.C. Control Board Check."
• Confirm CB red "POWER OK" LED is on. If CB red "POWER OK" LED is flashing
(indicating a full bin), check BC. Move ice away from BC actuator paddle. If CB
red "POWER OK" LED continues to flash, see "II.D.1. Bin Control Check."
a) Power On Diagnosis: If CB red "POWER OK" LED is off, confirm 5A fuse is good.
Check for 115VAC at control switch #2 (R) to neutral (W) then at control switch #1 (P)
to neutral (W). If 115VAC is present on #2 (R) and not on #1 (P), replace control
switch. If 115VAC is present on control switch #1 (P), check for 115VAC at HPS (P)
to neutral (W) then HPS (BK) to neutral (W). If 115VAC is present at HPS (P) and not
at HPS (BK), HPS is open. See HPS Diagnosis below. If 115VAC is present at HPS
(BK), check for 10.5VAC at CB K7 #1 red wire to CB K7 #2 red wire. If 10.5VAC is not
present, check CT continuity. If open, replace CT.
WARNING
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