When turned on, the indication on the screen works, the track lifting works. but the main motor does not work. the diode on the board does not light up. 9 and 2 volts are coming from the transformer.

Sorry if I ask elementary questions, I'm a beginner in electronics just learning

 

Does the micro processor (top left on the pic) have power?

 

Чи має живлення мікропроцесор (зліва зверху на фото) живлення?
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Yes, there is a 3 volt supply

 

Do you have a copy of the 'reverse engineered schematic?
Take a few readings of the required LV sources.

 

Do you have a copy of the 'reverse engineered schematic?
Take a few readings of the required LV sources.

the voltage regulator M78L05 (RG2) has an input voltage of 16 volts and an output voltage of 1.4 volts. i will try to replace the regulator tomorrow

 

Do you have a copy of the 'reverse engineered schematic?
Take a few readings of the required LV sources.

I replaced the voltage regulator. There are 5 volts at the output, and 5 volts are also supplied to the processor. but the diode does not light up.

 

Do you have a copy of the 'reverse engineered schematic?
Take a few readings of the required LV sources.

When I accidentally shorted the second and fourth legs of the HD6 connector, the motor started and the diode lit up, but the main switch in the house was knocked out.Could this indicate that the microcontroller has no 0V?

 

no 0V?

What is "No 0v"?
Normally you should get a steady Lit LED when power up. and a flashing LED when the PWM signal is input (P4 of HD2).
The PWM signal into HD2 P4 is directed to, and isolated by the 4 pin OPto-isolator next to the HD2.

 

What is "No 0v"?
Normally you should get a steady Lit LED when power up. and a flashing LED when the PWM signal is input (P4 of HD2).
The PWM signal into HD2 P4 is directed to, and isolated by the 4 pin OPto-isolator next to the HD2.

Oh, I'm sorry, I wrote wrong about 0V. Is it normal that the XRES pin is constantly 5V, or does it mean that the microcontroller is in reset mode and cannot start executing the program?

 

Check the XRES pin on the micro you have on your board . see if it is in continous reset.

 

When turned on, the indication on the screen works, the track lifting works. but the main motor does not work. the diode on the board does not light up. 9 and 2 volts are coming from the transformer.

Sorry if I ask elementary questions, I'm a beginner in electronics just learning

What have you checked so far in the board?, main components such as transistors or Mosfets, are OK?, have you tested with multimeter?
Anything burned you see with your eyes?
Any corrosion or missing tracks?

 

Check the XRES pin on the micro you have on your board . see if it is in continous reset.

I have XRES on a constant voltage of 5 volts

 

What have you checked so far in the board?, main components such as transistors or Mosfets, are OK?, have you tested with multimeter?
Anything burned you see with your eyes?
Any corrosion or missing tracks?

I checked the main components. There is no visual damage either. I just can't understand why I have a constant 5 volts on the microcontroller. The datasheet says that there should be only a 5 volt pulse

 

I checked the main components. There is no visual damage either. I just can't understand why I have a constant 5 volts on the microcontroller. The datasheet says that there should be only a 5 volt pulse

The microcontroller should have Vcc pin which have constant 5v

 

See post of mine P#28
https://forum.allaboutcircuits.com/...readmill-stopped-working.147032/#post-1253371
The best way to test these boards is on the bench with 20hz speed control into HD2 pin#4.
IOW, by-pass the cconsole control all together.