Hoshizaki FD-1001MLH(-C) Service Manual page 63

a. Control Switch (K9 connector pins #1 and #2 white/black (W/BK) wires): 5VDC is
present from the white K5 connector pin closest to red K4 connector to the
K9 connector pin #1 white/black (W/BK) wire at all times. If 5VDC is not present,
the control board is bad and must be replaced. When the control switch is in the
"ICE" position, the control switch contacts are open. 0VDC is present from the white
K5 connector pin closest to red K4 connector to the K9 connector pin #2 white/black
(W/BK) wire. When in the "ICE" position, 5VDC is present from the K9 connector
pin #1 white/black (W/BK) wire to pin #2 white/black (W/BK) wire. When the control
switch is in the "DRAIN" position, the control switch contacts are closed. 5VDC
is present from the white K5 connector pin closest to red K4 connector to the
K9 connector pins #1 or #2 white/black (W/BK) wires. If 5VDC is not present the
control board is bad and must be replaced. 0VDC is present from the K9 connector
pin #1 white/black (W/BK) wire to pin #2 white/black (W/BK) wire.
b. High Pressure Switch (K9 connector pins #3 and #4 yellow (Y) wires): When the
high pressure switch is closed, 5VDC is present from the white K5 connector pin
closest to red K4 connector to the K9 connector pins #3 and #4 yellow (Y) wires.
If 5VDC is not present, the control board is bad and must be replaced. If 5VDC is
present to K9 connector pin #3 yellow (Y) wire and not to K9 connector pin #4 yellow
(Y) wire, the high pressure switch is open and the control board sounds a 3-beep
alarm. Check continuity across the high pressure switch (K9 connector pins #3 and
#4 yellow (Y) wires). When the high-pressure switch is closed, 0VDC is present
from the K9 connector pin #3 yellow (Y) wire to K9 connector pin #4 yellow (Y) wire.
When the high-pressure switch is open, 5VDC is present from the K9 connector pin
#3 yellow (Y) wire to K9 connector pin #4 yellow (Y) wire. If the high pressure switch
is open and the control board is not in alarm, the control board is bad and must be
replaced.
c. Gear Motor Protect Relay (K9 connector pins #5 and #6 white/orange (WO) wires):
When the gear motor protect relay contacts terminals 3 and 4 are open (gear motor
protect relay de-energized), 5VDC is present from the white K5 connector pin
closest to red K4 connector to the K9 connector pin #5 white/orange (W/O) wire.
If 5VDC is not present, the control board is bad and must be replaced. When the
gear motor protect relay contacts terminals 3 and 4 are closed (gear motor protect
relay energized), 5VDC is present from the white K5 connector pin closest to red
K4 connector to the K9 connector pins #5 and #6 white/orange (W/O) wires. Also
check from the K9 connector pin #5 white/orange (W/O) wire to K9 connector
pin #6 white/orange (W/O) wire. If 0VDC is present, the gear motor protect relay
contacts (terminals 3 & 5) are closed. If 5VDC is present, the gear motor protect
relay contacts (terminals 3 & 5) are open and the control board may be in an 8-beep
alarm. See "II.C.3.g) Gear Motor (8-beep alarm)."
d. Mechanical Bin Control (K8 connector pins #3 and #4 gray (GY) wires): When the
mechanical bin control proximity switch is closed (calling for ice), 5VDC is present
from the white K5 connector pin closest to red K4 connector to the K8 connector pin
#3 and #4 gray (GY) wires. If 5VDC is not present, the control board is bad and must
be replaced. If 5VDC is present to pin #3 gray (GY) wire and not to pin #4 gray (GY)
wire, the mechanical bin control proximity switch is open. See "IV.D.2. Mechanical
Bin Control Check."
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