K8055 PWM giving voltage, not open collector

Hi all,

I’m having an issue with my k8055 board. The pwm1 terminal is giving a 5v signal, while the pwm2 terminal is giving the correct open collector signal. Any idea what might be causing this?


It seems the base driving voltage of transistor T1 is output from the PWM1 terminal.
Possible cause:

  • Emitter terminal of transistor T1 is not properly soldered to GND.
  • Transistor T1 is defective.