Electrical Troubleshooting - 5/6 Series - AIRLESSCO LP460 Service & Operation Manual

TROUBLESHOOTING -
CAUSE
Control Settings
Fuse
Power Source
Thermal Overload
Pressure Control Assembly
(Board)
Motor
Sensor
Pressure Control
Knob (Potentiometer)
Pressure Control Assembly
(Board)
30
Machine does not start (5/6 Series)
STEP 1: After making sure that the machine is plugged into the wall, verify that the
on-off switch is in the ON position and that the pressure control knob is turned all the
way to the right (clockwise for maximum pressure).
STEP 2: Using your multi-meter, test the fuse for continuity or replace with a new
fuse. If the fuse reads good, move on to step three.
STEP 3: Using a Phillips Head screwdriver, remove the four screws holding the
pressure control assembly. Locate the light on the board indicating there is power (it
will be red or green). If light is OFF proceed to step four. If light is ON go to step six.
STEP 4: Locate the L1 and L2 terminals on the board, and then using your multi-me-
ter check to make sure you have 110 volts AC across the two terminals (the cord wires
will still be attached). If there is no voltage at these leads, there is no power getting
to the machine. Check your power source (outlet, circuit breaker, extension cord, and
power cord). If you have AC voltage at the L1 and L2 terminals, go to step 5.
STEP 5: Disconnect the two red motor leads (S1 & S2) and test for continuity between
them. No continuity means that the thermal coupler has opened due to excessive motor
heat. If the motor is still hot to the touch, allow it to cool and then retest. If the motor
is cool and there is not continuity on the red leads, contact your local Leeson repair
facility to repair/replace the thermal coupler. Continuity shows that the motor's thermal
coupler has not tripped. Proceed to step six.
STEP 6: If everything checks out in steps one through five and the power indicating
light is still out, replace the pressure control assembly.
STEP 7: Remove the motor brush covers and turn the machine on. Set the potentiome-
ter (POT) at maximum pressure and check for DC voltage across both brush terminals.
You should read greater than 80 volts DC. IF YOU DO NOT HAVE DC VOLTAGE
GO TO STEP EIGHT. If you have DC voltage, turn the machine off and unplug it from
the wall. Check to make sure that the brushes are making good contact with the arma-
ture. Replace the brushes if they are less than 3/8" long. If the brushes are good, replace
the motor.
STEP 8: Plug another sensor into the board and perform the zero calibration proce-
dure. If the machine starts to run, the sensor was bad. If there is no replacement sensor
available, use a multi-meter to test the resistance across the red and black wires of the
sensor (be sure to test at the plug). You should read 1.5 - 3.5k ohms. A faulty sensor
usually reads no continuity (open). If the sensor passes all the tests move to step nine.
STEP 9: Plug another potentiometer (POT) into the control board. If the machine
starts, the old POT is bad. When replacement POT is not available, remove the POT
lead (with the machine turned off) from the control board and test the resistance be-
tween the red and black wires (be sure to test at the plug). The resistance should read
between 8-12k ohms if it is outside of this range replace the POT.
STEP 10: If you do not have DC voltage at the motor brushes and all of the compo-
nents check out fine in steps eight and nine, replace the pressure control assembly.
STEPS (SEE FIGURE 23)