Hi. I'm new to this forum, my first post. Welcome all. I have a problem with MC2100E Rev C controller in Proform PF 3.6 threadmill. Everything works except motor isn't spinning and LED on board will not flash. Bridge rectifier has been shorted to ground accidentally and R39 was open circuit. No other faulty components. Micro does receive PWM signal but there is nothing on outputs for SCR and IGBT but previously I was getting signals for both but still there was only 5v on motor terminals. Don't know what happened as I'm at this board on and off in last few months. Tried SCR but think I got fake ones from Ali. Red LED remains solid all the time. Any ideas?

 

What SCR in the motor circuit??
Is there input to the Mosfet or IGBT gate driver?

 

SCR is S8025L and IGBT driver IR2127S has nothing on the input.

 

Ensure you have the LV to HD2 OK, you appear to have the SMPS LV DC version which is often a source of failure.
The mains transformer source types are a little more reliable.

 

I do have +12V at pin 1 HD2 and this version does have a transformer. Is it normal that I measure 60 Ohms between pin 1 and 3 of SCR? Can't find reliable info on that.

 

Is that in circuit or out?

 

Out of circuit, took me a while to figure it out as both IGBT and SCR were measuring ok in circuit.

 

With an ordinary fluke style MM you should read open circuit on all pins when out of circuit.

 

Thanks, ones I got from aliexpress were measuring 120 Ohms between pins 1 and 3 and pin 2 was connected to tab, original SCR has OC between pin 2 and tab so got puzzled. They were definitely fakes, see pics. Component tester detected them as NPN BJT and they looked nasty, see pics. I can't source S8025L in UK from reliable source. Is there a good known alternative?