Control Board Check - Hoshizaki SRC-14H Service Manual

C. Control Board Check
Before replacing a control board that does not show a visible defect and that you suspect
is bad, always conduct the following check procedure. This procedure will help you verify
your diagnosis.
1) Check CB S1 dip switch settings to assure that they are in the factory default position.
For factory default settings, see "III.B.1. Default Dip Switch Settings."
Note: S1 dip switch 7 determines bin control application:
BC1 (infrared sensor) with BC2 (mechanical backup): S1 dip switch 7 in the "ON"
position.
BC (mechanical stand-alone) (Standard Ice Storage Bin): S1 dip switch 7 in the
"OFF" position.
2) Move the power switch to the "ON" position and move the control switch to the "ICE"
position. The CB "POWER OK" LED turns on. Diagnosis "POWER OK" LED: Check
that the CB "POWER OK" LED is on. If not, check for proper supply voltage (115VAC)
input to the control transformer (power switch, breaker, and fuse). Next, check for proper
low-voltage (24VAC) output from the control transformer and the 1A fuse is good. Check
for 24VAC at CB K8 #1 (W/R) to CB K8 #2 (LBU). If 24VAC is present and CB "POWER
OK" LED is off, replace CB.
3) BC1 (infrared sensor) Power Supply (K6 connector): CB supplies 20VDC to BC1
and BC1 green LED is on. Diagnosis: Check that BC1 green LED is on. If not, check
for 20VDC between CB K6 #1 (DBU) and CB K6 #3 (BR). See Fig. 1. If 20VDC is not
present, replace CB. If 20VDC is present, confirm that the yellow LED is not flashing
or steady. If BC1 yellow LED is on or flashing, move ice away from lens. If no ice is
present, clean the lens with a warm, clean damp cloth. If cleaning the lens does not
work, replace BC1 (infrared sensor).
BC1 (infrared sensor) (20VDC)
Closed
20VDC K6 #1 (DBU) to K6 #3 (BR)
20VDC K6 #1 (DBU) to K6 #2 (W)
0VDC K6 #2 (W) to K6 #3 (BR)
BC1 (infrared sensor) (20VDC)
Open (yellow LED flashing or steady)
20VDC K6 #1 (DBU) to K6 #3 (BR)
0VDC K6 #1 (DBU) to K6 #2 (W)
20VDC K6 #2 (W) to K6 #3 (BR)
K6 #3
Brown (BR)
K6 #2
White (W)
K6 #1
Dark Blue (DBU)
Fig. 1
22
Red Positive
3 20VDC
Test Lead
2
1
Black Negative
Multimeter
Test Lead
•
K6 Connector
BC1 (Infrared Sensor)