Speed Control Potentiometer, Replace the D. C. control board

	Speed Control Potentiometer	This is a 0 to 400 ohm or 0 to 500 ohm, 10-turn
		potentiometer. WITH POWER OFF: remove the
		red, white, and black leads from terminals S1, S2,
		S3. With a digital multimeter, check the ohm
		reading across the red to black leads. This ohm
		reading should be a steady 400-ohm, or 500-ohm,
		through the entire 10-turn rotation of the
		potentiometer. Check for shorts or opens or
		unsteady, ohm reading, if potentiometer is
		defective, replace. If the potentiometer checks OK,
		and there is no output at terminals A1 and A2,
		replace the D. C. control board.
	Reversing Switch	If there is D. C. voltage output from the motor
		control board, but the conveyor drive motor is not
		running, check the D.P.D.T. reversing switch.
	Conveyor Drive Motor	Check the conveyor drive sprocket for tightness.
		Disconnect the motor, check the red and black
		motor leads for opens, shorts or grounds. Check
		the brushes for excessive or	abnormal wear.
		Replace as needed. Reconnect motor. Test for
		operation. If motor does not run, replace.
Conveyor will not	Voltage Supply	Check incoming voltage supply at line 1 to neutral.
run(S/N 4390 to		There should be a voltage reading of 120 VAC. If
Q190771000 Series)		no present, check breakers. 3 Amp Fuse. This
(S/N 4390-		conveyor fuse is located on the front panel.
Q147901200 Series)		Replace if defective.
	Fuseholder	Check and/or Replace.
	Fan Switch	See procedure for checking on Page 20.
	Conveyor Switch	Same procedure as for fan switch.
NOTE:	(Dual Belt Ovens)	Dual belt ovens utilize 2 complete independent
		conveyor drive systems. The trouble shooting
		procedures are the same as single belt ovens,
		except that the dual belt ovens use one each of the
		following: one "A" D. C. control board and one "B"
		D. C. control board.
	Speed Adjustment	This is a 0 to 5 K ohm, 10 turn potentiometer With
	Potentiometer	power off, remove the red, black and white pot
		leads from the motor control board at terminals P1,
		P2 and P3. With a digital multimeter, check the
		ohm reading across the red lead (P3) to the black
		lead (P1). This reading should be 5 K ohms ± 5%
		as the pot is rotated from low to high. Place the
		meter leads on the red lead (P3) and on the white
		lead (P2) Rotating the pot. slowly, from low to high,
		the meter reading should show an even transition
		from O to 5 K ohms ± 5%. There should be
	DC Motor Control Board	Check for 120 VAC input to the control board at
		terminals L1 and L2. If not present, check the
		conveyor switch and wiring back to 3-amp fuse and
		then back to power source if necessary. If 120 VAC
		is present at L1 and L2, check the VDC output at
		terminals A+ and A-. If a DC voltage is not present,
		check the 4 amp and the 1 amp fuses on the
		control board. Also reset and check the mini
		breaker in the armature line to the gearmotor. If
		120 VAC is present at terminals L1 and L2, but DC
		voltage is not present at A+ and A-, providing the 1
		amp and 4 amp fuses are good, replace the board.
		If DC voltage is present at A+ and A-, but motor
		does not run, check gear motor as follows.

Impinger I -–1000 Series Service Manual - Domestic

Speed Control Potentiometer

This is a 0 to 400 ohm or 0 to 500 ohm, 10-turn

potentiometer. WITH POWER OFF: remove the

red, white, and black leads from terminals S1, S2,

S3. With a digital multimeter, check the ohm

reading across the red to black leads. This ohm

reading should be a steady 400-ohm, or 500-ohm,

through the entire 10-turn rotation of the

potentiometer. Check for shorts or opens or

unsteady, ohm reading, if potentiometer is

and there is no output at terminals A1 and A2,

replace the D. C. control board.

Reversing Switch

If there is D. C. voltage output from the motor

running, check the D.P.D.T. reversing switch.

Conveyor Drive Motor

Check the conveyor drive sprocket for tightness.

Disconnect the motor, check the red and black

motor leads for opens, shorts or grounds. Check

the brushes for excessive or

abnormal wear.

Replace as needed. Reconnect motor. Test for

operation. If motor does not run, replace.

Conveyor will not

run(S/N 4390 to

Q190771000 Series)

no present, check breakers. 3 Amp Fuse. This

conveyor fuse is located on the front panel.

Q147901200 Series)

See procedure for checking on Page 20.

(Dual Belt Ovens)

Dual belt ovens utilize 2 complete independent

conveyor drive systems. The trouble shooting

procedures are the same as single belt ovens,

following: one "A" D. C. control board and one "B"

D. C. control board.

Speed Adjustment

power off, remove the red, black and white pot

P2 and P3. With a digital multimeter, check the

ohm reading across the red lead (P3) to the black

lead (P1). This reading should be 5 K ohms ± 5%

as the pot is rotated from low to high. Place the

meter leads on the red lead (P3) and on the white

the meter reading should show an even transition

from O to 5 K ohms ± 5%. There should be

DC Motor Control Board

Check for 120 VAC input to the control board at

terminals L1 and L2. If not present, check the

conveyor switch and wiring back to 3-amp fuse and

is present at L1 and L2, check the VDC output at

check the 4 amp and the 1 amp fuses on the

control board. Also reset and check the mini

breaker in the armature line to the gearmotor. If

120 VAC is present at terminals L1 and L2, but DC

voltage is not present at A+ and A-, providing the 1

amp and 4 amp fuses are good, replace the board.

If DC voltage is present at A+ and A-, but motor

does not run, check gear motor as follows.