I see a number of discussions about MC2100 in this forum, but I haven't seen one with my symptoms.
My treadmill stopped working. It has MC2100WAM motor controller.
I do not have EE education, but I'm handy with electronics to some extend....
The Console seems to be functional and it moves the incline motor. The main motor, however, refuses to move the belt.
I see no visual indication that any component is burned/damaged.
The diode bridge has 120V AC input and 107V DC output. Is this voltage drop expected from the diode bridge?
Blue wire in HD2 harness (WPM from Console) does carry PWM. I don't have oscilloscope, but my multimeter can measure freq duty cycle, which is from 20% at the lowest speed to 85% at the highest, controlled from the Console.
I have tested the motor by powering it with 12V SLA battery and it works.
LG3 and LG4 terminals (DC output to the motor) give 0V, so it looks like the board doesn't want the motor to move.
MC1900 chip does get 5V (measured btw Pin 10 - Gnd and Pin 20 - V+).
If I connect pin9 to pin10 (Gnd) of MC-1900 chip, then the LED lights up. This has no effect on the motor.
Power resistor 7W 3.3K (on two tall legs) heats up a lot - to the point that it starts smelling in few minutes and I have to turn the power off. The voltage drop across this resistor is 91V with 120Hz frequency, which I assume comes from the diode bridge. Applying Ohm's law I=U/R=91/3300=0.03A. If the current is so small, why does it burn then? What am I missing here?
Troubleshooting instructions say that LED being off indicates no AC voltage to the controller, which is not the case here.
To summarize my symptoms:
1. LED is off
2. Power resistor 3.3K 7W is extremely hot
3. Zero voltage to the motor output (terminals LG3, LG4)
I started looking at components close to the burning power resistor and noticed the output to Pin7 of MC1900 (according to the attached schematics).
Pin7 of MC1900 IC is called "AC power Voltage sense" in the schematics. I've measured it to be 4.9V (btw Pin10 and Pin7), but it seems to be DC, not AC.
What can make the power resistor burn?
Everything else seems to work: PWM from the Console, incline motor, voltage to MC1900 IC.
The troubleshooting guide says Red wire in HD2 harness is 9V, but in my case it is 15V. I assume that I have a different variation of MC2100 board.
Last observation: the LED blinks briefly (1/10sec or less) when I turn the power on. This is the only time the LED lights up.
I appreciate any help with the troubleshooting.
My treadmill stopped working. It has MC2100WAM motor controller.
I do not have EE education, but I'm handy with electronics to some extend....
The Console seems to be functional and it moves the incline motor. The main motor, however, refuses to move the belt.
I see no visual indication that any component is burned/damaged.
The diode bridge has 120V AC input and 107V DC output. Is this voltage drop expected from the diode bridge?
Blue wire in HD2 harness (WPM from Console) does carry PWM. I don't have oscilloscope, but my multimeter can measure freq duty cycle, which is from 20% at the lowest speed to 85% at the highest, controlled from the Console.
I have tested the motor by powering it with 12V SLA battery and it works.
LG3 and LG4 terminals (DC output to the motor) give 0V, so it looks like the board doesn't want the motor to move.
MC1900 chip does get 5V (measured btw Pin 10 - Gnd and Pin 20 - V+).
If I connect pin9 to pin10 (Gnd) of MC-1900 chip, then the LED lights up. This has no effect on the motor.
Power resistor 7W 3.3K (on two tall legs) heats up a lot - to the point that it starts smelling in few minutes and I have to turn the power off. The voltage drop across this resistor is 91V with 120Hz frequency, which I assume comes from the diode bridge. Applying Ohm's law I=U/R=91/3300=0.03A. If the current is so small, why does it burn then? What am I missing here?
Troubleshooting instructions say that LED being off indicates no AC voltage to the controller, which is not the case here.
To summarize my symptoms:
1. LED is off
2. Power resistor 3.3K 7W is extremely hot
3. Zero voltage to the motor output (terminals LG3, LG4)
I started looking at components close to the burning power resistor and noticed the output to Pin7 of MC1900 (according to the attached schematics).
Pin7 of MC1900 IC is called "AC power Voltage sense" in the schematics. I've measured it to be 4.9V (btw Pin10 and Pin7), but it seems to be DC, not AC.
What can make the power resistor burn?
Everything else seems to work: PWM from the Console, incline motor, voltage to MC1900 IC.
The troubleshooting guide says Red wire in HD2 harness is 9V, but in my case it is 15V. I assume that I have a different variation of MC2100 board.
Last observation: the LED blinks briefly (1/10sec or less) when I turn the power on. This is the only time the LED lights up.
I appreciate any help with the troubleshooting.
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