November 1999
33
COUNTER TOP IMPINGER
Fan Switch
Check continuity between switch terminals. Replace
as needed.
Conveyor Control
Transformer
Check for supply voltage at primary of transformer. If
no voltage is present, trace wiring back to fan switch.
Check for 24VAC at transformer secondary. If no
voltage is present, replace transformer.
Speed Adjustment
Potentiometer
This is a 5K ohm potentiometer. WITH POWER OFF:
Remove the leads from the motor control board at
terminals P1, P2, P3. With a digital meter, check the
ohm reading across the red and black leads. This
reading should be 5K ohms (± 10%) as the pot. is
rotated from low to high. Place meter leads on red
and white lead. Rotating the pot. slowly from low to
high, the meter reading should show an even
transition from 0 to 5K ohms (± 10%). There should
be no dead or open spots throughout the rotation of
the pot. Check all three (3) leads to ground. There
should be no continuity to ground. If any of the above
checks fail, replace the pot.
Conveyor Control Board
Check for 24 VAC input to conveyor control. If no
voltage is present, trace wiring back to transformer. If
voltage is present at L1 and L2, check for D.C. output
at terminals A+ and A-. If there is AC voltage input,
but no D.C. voltage output, replace conveyor control
board.
Conveyor Gear Motor
If there is D.C. voltage output from the conveyor
control, but the motor does not run, check the mini-
breaker (0.7 Amp). Check motor leads for opens,
shorts or continuity to ground. If motor fails above
test, replace motor.
Conveyor will not run
S/N 4000480 and Below
Conveyor
Check conveyor drive coupling to be sure that it is
tight. Also check to see that coupling is engaged with
conveyor drive shaft. Check for any mechanical
misalignment or improper adjustment, also check for
worn bearings. A conveyor belt that is too tight will
cause excessive bearing wear and sometimes-
irregular speed.
Power Supply
Check for steady supply voltage to oven. If voltage is
unsteady, contact power company.
Transformer
Check for steady A.C. voltage output from transformer
and replace as needed.
Conveyor Control
Check for steady D.C. voltage output from conveyor
control. If D.C. voltage output is unsteady, check
conveyor potentiometer (see "Speed Adjustment
Potentiometer" under Conveyor will not run). If the
potentiometer checks good, and the D.C. voltage is
unsteady, replace conveyor control.
Conveyor speed
varying or intermittent
D.C. Gearmotor
Check motor brushes for excessive arching and/or
unusual wear. Replace brushes or gearmotor as
needed.
