STERO SD3 Series, Service And Parts Manual

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1) Verify no debris is present in tank that
could cause float to malfunction.
2) If no debris is interfering with float
operation, control board has
malfunctioned.
No Wash Cycle
1. Verify the following.
A. OPERATING CONDITIONS are satisfied as
stated at the beginning of this section.
B. Control board is programmed to operate as
an SD3.
C. Dishwasher is full of water.
NOTE: The DOOR LED will be lit when the door
switch 1LS is closed.
D. Chamber door is closed.
E. The MICRO LED is flashing at a rate of 1
sec on 1 sec off, and the DOOR and LOW
WATER LEVEL LEDs on control board are
on.
F. Motor thermal circuit breaker is not tripped.
NOTE: The WASH LED on relay board will be on
whenever voltage is applied to the pump motor.
2. Open and close chamber door. Wash cycle
should begin. Check to see if the WASH LED on
relay board is on.
Fig. 27
A. If the WASH LED is on, but the pump does
not energize, check operation of K8 relay.
1) If relay K8 functions normally, check
remaining wash pump circuit.
B. If WASH LED is not on, test pump motor
circuit by shorting the two WASH pins of J14
on the control board together.
Fig. 28
1) If the wash pump energizes when pins
J14 are shorted together, remove short
then open and close dishwasher door.
If wash cycle does not start, replace
control board.
NOTE: When machine calls for wash (K8 energized),
voltage across J6-6 and ground will be zero or a few
millivolts. Circuit activation can be verified by
measuring 5VDC voltage across the control board
+5VDC test pad and J6-6 when the wash circuit is
energized.
2) If WASH LED does not light and wash
pump does not energize when J14 is
shorted, check control board voltage
output to relay board across J6-6
(control board) and ground = 0VDC
(J6-6 and +5VDC test pad = 5VDC).
a. If voltage measurements indicate
circuit is active, verify wiring to
relay board is correct. If correct,
replace relay board.
b. If voltage measurements are not
present, replace control board.
c. If voltage measurements remain
constant at approximately
4.5VDC, check the door interlock
circuit 1LS.
No Tank Heat
1. Verify the following.
A. OPERATING CONDITIONS are satisfied as
stated at the beginning of this section.
B. Control board is programmed to operate as
an SD3.
C. Dishwasher is full of water and tank
thermistor is good.
D. Tank temperature is programmed properly
and machine is calling for heat.
SD3 Series - TROUBLESHOOTING
Page 31 of 37 F45576 (1015)