Lincoln 1100 Series Service Manual page 30

Temp display
inaccurate erratic, or
inoperative
Time Display inaccurate
erratic, or inoperative
30
Thermocouple Probe
Power Supply
Time/Temp Display
Conveyor Drive (Stepper)
Motor
Magnet
Hall Effect Sensor
Conveyor Drive (Stepper
Control)
time/temp display terminals #9 and 10. Measure the
resistance of the thermistor probe. See chart on page
44 showing probe resistance at various oven
temperatures. If these readings are not achieved,
replace the thermistor probe.
Place your pyrometer thermocouple into the center of
the top finger. Measure D.C. millivolts at terminals 9 and
10 on the time/temp display. See thermocouple chart on
page 36 for proper readings. Connect temperature
meter to thermocouple at terminals 9 & 10 on back of
the time/temp display. (Be sure to maintain proper
polarity on thermocouple connections.) Compare actual
oven temperature with the reading at the time/temp
display. If the temperature readings match, recalibrate or
replace time/temp display. If the readings do not match,
replace thermocouple probe.
If a strange or unusual behavior is experienced, such as
a rolling of numbers, or lock-up at a given number, first
check for a display circuit lock-up. This may be caused
by a voltage spike or surge in the incoming power lines.
To eliminate this condition, remove power from the
time/temp display by shutting off the main fan switch for
15 seconds. This should eliminate the problem. If this
does not solve the problem, it may becoming in through
the Commercial power lines. Suggest that customer
contact their power company for evaluation.
Perform the power supply check, the thermistor probe
check, and then perform the time/temp simulator test.
Refer to page 45 for instructions. Remember, when
using the time/temp simulator, remove all leads from the
back of the time/temp display except the 3 power leads.
After completion of the test, and if re-installing time/temp
display back in the oven, the dip switches must be reset
for oven operation, and the time/temp display must be
re-calibrated. If readings are not achieved, replace
display
Perform all checks as in the above evaluation. If the time
check is okay, refer to the next section.
Check to see if the conveyor drive (stepper) motor is
running. If motor is not running, refer to "Conveyor will
not run" on page 29.
Check to insure that the magnet (cemented to shaft of
conveyor drive [stepper] motor) has not been damaged,
Check for any physical damage to Hall Effect sensor
(mounted on conveyor drive [stepper] motor). Check all
wiring and connections for damage. If the motor is
running, the magnet is in place, but the display shows"--
:--" the Hall Effect Sensor may be defective or
improperly connected.
Check all connections for tightness or proper location
and check all wiring for visible damage. Replace as
needed. If there is still no time display and all the above
have checked out, replace the stepper control.
Impinger II –1100 Series Service Manual - Domestic