Lincoln 1400 Series Temperature Control Board, Check for 120 VAC input to temperature control

	Temperature Control Board	Check for 120 VAC input to temperature control
		board. If not present, check wiring from Hi-Limit to
		temperature control board. Turn the temperature
		adjustment dial to the maximum temperature position.
		Check for 120 VAC at coil of mercury contactor(s).
		Next, short the leads of thermocouple on the
		temperature control board, check for 120 VAC at coil
		of mercury contactor(s). If voltage is not present,
		replace temperature control board. If voltage is
		present, proceed.
	Thermocouple Probe	Remove thermocouple leads from the temperature
		control board, and measure the millivolt output of the
		leads. Refer to chart (page 25) in adjustment section
		for proper millivolt readings.
	Mercury Contactor(s)	Check for 120 VAC to the contactor coil. If voltage is
		present and contactor will not activate, replace the
		contactor(s). Also check each contactor for proper
		high voltage input and output.
	50 Amp Fuses	If there is no high voltage input to the mercury
		contactor(s), check the 50 amp fuses and replace if
		necessary.
	Heater Elements	Check the Amp. draw on each hot leg for proper load.
		Check the specification plate for rating information. If
		the Amp. draw is low or high, check the individual
		elements for opens, shorts, and proper resistance. To
		check resistance of the elements, turn off the power!
		Remove all leads from the elements and use an
		accurate digital VOM. The element resistance should
		be as follows: 208V - 9.8 ohms approx. 220V - 10.5
		ohms approx. 240V - 13 ohms approx. If all readings
		are not correct, replace elements as needed.
Oven heats with	Mercury Contactor(s)	The mercury contactor has probably malfunctioned in
switch off		the closed position. If there is no voltage to the
		operating coil, but there is high voltage at the
		contactor output, replace the mercury contactor.
Conveyor will not run	Voltage Supply (Export Ovens)	Check incoming voltage supply, check breakers and
		reset if required. For some export ovens there is a
		control circuit step down transformer. This transformer
		steps down supply voltage to 120 VAC. If conveyor
		will not run, the secondary of this transformer must be
		checked for 120 VAC output. Check specific oven
		model schematic for circuit location.
	Speed Adjustment	This is a 0 to 10K ohm, 1 turn potentiometer. With
	Potentiometer	power off, remove the black and white pot leads from
		the motor control board at terminals P1 and P2 with a
		digital multimeter, check the ohm reading on the black
		lead (P2) and the white lead (P1). Rotating the pot,
		slowly, from low to high, the meter reading should
		show an even transition from 0 to 10K ohms ± 5%.
		There should be no dead or open spots through out
		the 1 turn of the pot. Check both leads to
		ground.There should be no continuity to ground. If any
		of the above checks fail, replace the pot.
	DC Motor Control Board	Check for 120 VAC input to the control board at
		terminals L1 and L2.If not present, check 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 120 VAC is present at terminals L1 and L2, but
		DC voltage is not present at A+ and A-, verify fuses
		are not blown, if fuses check ok, replace the board. If
		DC voltage is present at A+ and A-, but motor does
		not run, check gear motor as follows:

Impinger I – 1400 Series Advantage Service Manual – Dom & Int’l 19