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Indications of Speed/Needle Position Sensor
The main shaft speed and needle position sensor
mounts to the main shaft near the back hand wheel.
(Figure 13.1) It is composed of a disk with two
encoder regions. The outermost region consists of
100 small segments to provide speed feedback to the
control system. The inner region consists of only two
segments (an "on" region and an "off" region).
Speed LED
Figure 13.1
There is a forked circuit board containing an emitter
and a receiver for each of the two encoder regions.
With the front cover open and the power and control
pods hooked up and powered on, you can rotate the
hand wheel and see the green LEDs flash to indicate
that the encoder is working properly.
The green "Speed" LED on the left side of the board
should flash on and off at a rate of 100 flashes per
revolution as you rotate the hand wheel. The green
"Needle" LED on the right should turn on to indicate
the needle is in the "Up" position (the take-up lever
is in its highest position) and turn off to indicate the
needle is in the "Down" position.
Careful inspection of these LEDs as you rotate the
hand wheel with the power on will tell you whether
the encoder is functioning properly. Damage to the
encoder disk or any build-up of dust, oil or other
material can impede the transfer of light through the
transparent portion of the disk and cause the encoder
to miss some pulses.
Power Supplies
One 24V DC power supply is mounted to each side
Page 36
of the quilting machine within the C-Pod and P-Pod
housings. These power supplies combine on the
C-Pod control board to provide a total of 48V DC to
the motor. Each power supply has a dim green LED
that is on when machine power is turned on. If the
green LED is on, then that indicates the power supply
is functioning properly. To view the green LED, turn
off the lights in the room and look into the top of the
black plastic housing that mounts the power supply
to the side of the quilting machine. Remember that
there is a power supply on each side of the machine.
Needle
LED
Symptoms of a Failed Power Supply
If one of the 24V power supplies has failed, the
other power supply will provide enough power to
the machine to boot up and power the handlebars.
Everything may look normal until the "Start" or
"Needle Up/Down" button is pressed. With only 24V,
the motor will not turn and a message on the handles
will indicate either "Needle Sense Failure" or "Needle
Sense Failure During Walk." If this happens, check
the two power supplies as described previously by
removing the C-Pod and P-Pod housings and looking
into the top of the black plastic power supply covers
for the green LED (a dark room is usually necessary to
see the green LEDs). If one of the supplies has failed,
the LED will not be lit and the power supply should be
replaced. Remember when removing power supplies
to re-apply the pink insulating material to the power
supply to prevent the metal heat sinks from hitting
the machine casting.
If both power supplies have failed, there will be no
power at all to the machine (no handlebar screens, no
lights, etc.). However, it is more likely that the fuse
has blown if there is no power to the machine than
that both power supplies have failed, so be sure to
check the F2 fuse. The quickest way to check the fuse
is to test for continuity between the center pin of the
switch (SW1) and pin 1 of either J2 or J3. A basic Ohm
Baby Lock Crown Jewel Service Manual
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