Janome QMP16SU Manual page 66

• Adjust rotation of main shaft encoder disc as needed to be sure Needle Up stop position occurs when
the take-up lever is at its highest point).
• If Needle Sensor Test passes but you are still getting a Needle Sensor Failure message, then run the
burn-in calibration to try to resolve the error.
Other causes of a Failed Needle Sensor Test
• Main Shaft Encoder Cable is unplugged from the Control board or the Encoder Board
• Main Shaft Encoder Cable is damaged
• Main Shaft Encoder Board is damaged
 NOTE: For any of the above three issues, with the machine opened up, the Needle LED on the
right side of the Main Shaft Encoder Board should turn ON to indicate the UP position and OFF
to indicate the DOWN position. If the LEDs do not turn on at all, this is a good sign that the Main
Shaft Encoder board or cable have failed and should be replaced. The cable and board are typically
replaced together.
Keypad Test
The Keypad test verifies that the Janome QMP16SU is reading the handlebar buttons when they are
pressed.
• Press the Keyboard Test button. Then press one of the handlebar buttons. When you press the
key, the name of the key appears in a white box on the screen. When you release the key,
the name disappears.
X-Motion Sensor Test
Use the X-Motion Sensor test to verify functionality of the X-axis stitch regulator encoder (the encoder
mounted at the rear of the carriage).
• Press the X-Motion Sensor test button. Slowly move the machine left and right. You should hear a
pulsing beep that pulses faster as you move the carriage faster. A solid beep, no beep, or periods of
irregular beeping (with constant motion) indicate a problem with the X-axis encoder.
 NOTE: The most likely cause of a problem is a stitch regulator wheel that is not making consistent
contact with the track. Check the spring tension on the sensor assembly on the carriage to ensure
that it will easily return to the fully extended position after being compressed. Also ensure that the
track is straight with no dips or indentations and that it is clean and free of contamination. Other
causes are an unplugged or damaged cable or possibly an issue with the main control board.
Burn-in
The Janome QMP16SU machine requires a speed calibration that occurs during the standard burn-in
process at Janome when the machines are built. During burn-in, the machines start running at their
slowest speed, then gradually ramp up to the fastest speed and then back down again to a stop. This is
one complete burn-in cycle. As this occurs, the control board is sending a specific value to the motor driver
board to tell it to drive the motor a certain percent speed. The control board then looks at how fast the
motor is really going and compares it with the speed it should be going. For example, a Janome QMP16SU
machine set at 10% speed should be driving the motor at 180 RPM. If the motor is actually going slower
or faster than the specified speed, then the speed table that is stored in memory is adjusted by a small
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