Lincoln 1922, 1921 service manual

Page 9

 

Switch, Main Power

WITH POWER OFF: Check continuity between switch

 

 

terminals. Replace switch as needed.

 

Control transformer

Check for supply voltage to the primary of the control

 

 

transformer. If no voltage is present, trace wiring back

 

 

to the oven power relay. If voltage is present, check for

 

 

24 VAC at the transformer secondary. If there is

 

 

primary voltage but no secondary voltage, replace

 

 

control transformer.

 

 

Air pressure switch

Check for 208/240VAC to the air pressure switch. If no

 

 

voltage is present, trace wiring back to main power

 

 

switch. This normally open switch should close when

 

 

the main fan is activated. Refer to the “Removal and

 

 

installation” section for proper adjustment. Replace as

 

 

needed.

 

 

Switch, Infrared heater

Check for 208/240VAC to the Infrared heater switch. If

 

 

no voltage is present, trace wiring back to the air

 

 

pressure switch. WITH POWER OFF: Check continuity

 

 

between switch terminals. Replace switch as needed.

 

Conveyor motor

Check for supply voltage to the conveyor motor. If no

 

 

voltage is present, trace wiring back to the primary of

 

 

the control transformer. If voltage is present and the

 

 

motor will not run, check the motor windings for opens

 

 

or shorts.

 

 

 

WITH POWER OFF: Check the motor windings as

 

 

follows:

 

 

 

Grey to black - 236 ohms

approx.

 

 

Grey to brown - 236 ohms

approx.

 

 

Brown to black - 472 ohms

approx.

 

 

If any of the above fails, replace conveyor motor.

 

Capacitor, conveyor motor

Check for shorts or grounds. Replace capacitor as

 

 

needed.

 

 

 

WARNING: Capacitor has a stored charge, discharge

 

 

before testing.

 

 

Switch, conveyor reversing

Check continuity between switch terminals. Replace

 

 

switch as needed.

 

 

Oven control

If there is supply voltage to the motor, and the motor,

 

 

motor capacitor, and reversing switch check good,

 

 

replace the oven control.

 

Conveyor motor runs, but there

Oven control

Check for output voltage from oven control to hall effect

is no speed display

 

sensor (sensor is located in conveyor motor). Measure

 

 

voltage at the motor connector, red wire and yellow

 

 

wire. Voltage should be approx. 10VDC. If no voltage is

 

 

present, trace wiring back to oven control. If there is no

 

 

voltage present at the oven control, replace the oven

 

 

control.

 

 

Conveyor motor

If there is voltage supplied to the hall effect sensor,

 

 

check for a frequency output from the hall effect

 

 

sensor. Measure frequency across the yellow and white

 

 

wires at the motor connector. Frequency reading

 

 

should be approx. 25 – 100 Hz. If these readings are

 

 

not achieved, replace conveyor motor. If the readings

 

 

are achieved, proceed.

 

 

Oven control

If the hall effect sensor readings are correct, but there

 

 

is no speed indicated on the display, replace the oven

 

 

control.

 

DTF – 1920 Series Service Manual

9

Image 9
Contents Dual Technology Finisher Dual Technology Finisher Schematic Diagram Model 1922 S/N 8001207 and Below Model 1921 / 1922 S/N 8001208 and Above Troubleshooting Guide With Power on and Thermocouple Digital multimeter Page Main FAN Replacement MOTOR, Main FAN ReplacementSWITCH, ON/OFF SWITCH, Standby Replacement RELAY, Time Delay ReplacementFuse Holder Replacement Circuit BREAKER, Main Motor ReplacementRELAY, Main Heater RELAY, Infrared Heater Replacement Reversing SWITCH, Conveyor ReplacementConveyor Motor Replacement CAPACITOR, Conveyor Motor ReplacementAIR Pressure Switch Replacement AIR Pressure Switch AdjustmentHeating ELEMENT, Main Replacement THERMOSTAT, HI-LIMIT ReplacementHeating ELEMENT, Infrared Replacement Main Control ReplacementPage This page intentionally left blank General View Page Control BOX View Page Rear View Page Conveyor Model 1921 8001200 and Above