| Speed Adjustment | This is a 0 to 10 K ohm, 1 turn potentiometer. With |
| Potentiometer | power off, remove the black and white pot leads |
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| from the motor control board at terminals P1, P2. |
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| Place the meter leads on the black lead (P2) and |
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| on the white lead (P1). Rotating the pot., slowly, |
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| from low to high, the meter reading should show an |
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| even transition from 0 to 10 K ohms ± 5%. There |
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| should be no dead or open spots through out the 1 |
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| turn of the pot. Check both leads to ground. There |
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| should be no continuity to ground. If any of the |
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| above checks fail, replace the pot. |
| DC Motor Control Board | Check for 208/240 VAC input to the control board at |
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| terminals L1 and L2. If not present, check wiring |
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| back to the oven fan switch. If voltage is present at |
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| L1 and L2, check both fuses on control board (8A |
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| line and 1A armature), check the VDC output at |
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| terminals A+ and |
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| terminals L1 and L2, and DC voltage is present at |
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| A+ and |
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| motor as follows. |
| Conveyor Gear Motor | If DC voltage is present at A+ and A- and the motor |
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| does not run, first check the mini breaker and then |
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| the conveyor. Refer to the next possible cause. |
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| Check the leads to the motor for evidence of any |
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| shorts or opens, and each lead to ground. Check |
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| motor brushes. From the top of the motor, rotate |
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| motor shaft to determine if there is a locked rotor or |
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| a locked gear box (use care so magnet and H.S. |
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| board are not damaged). Replace motor as |
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| needed. |
| Conveyor | Check for any mechanical misalignment. Also |
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| check for worn bearings. A conveyor belt that is |
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| over tightened will cause excessive bearing wear |
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| and sometimes, irregular speed. |
Conveyor speed varying or | Power Supply | Check power supply at the DC control board for the |
intermittent |
| 208/240 VAC at board terminals L1 and L2. |
| Motor Control Board | Place the test meter probes on terminals A+ and |
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| (With speed potentiometer set to maximum speed |
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| (Approximately 2 minutes), the meter reading |
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| should be approximately 100 VDC (± 3%), if voltage |
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| is not steady within limits, then the board is |
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| probably bad. Always check the speed pot. Be |
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| sure it is okay before changing a board. This test is |
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| not always 100% accurate as this test is not |
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| performed at operating speeds. However, this test |
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| is the best method currently available. |
| DC Gearmotor | If the DC control board is steady, then the problem |
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| may be the motor or gearbox. Check the brushes |
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| in the motor for excessive arching and/or unusual |
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| wear. Check the motor and gearbox from |
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| instruction located on page 14 under "possible |
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| cause" listing "conveyor gear motor." |
| Magnet | Check to insure that the magnet (cemented to shaft |
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| of conveyor drive motor) has not been damaged, or |
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| come loose from motor shaft. Replace as needed. |
Impinger II | 15 |