Have you checked all the power components on the HS?
The DC ramp SCR , The Mosfet/IGBT, the Mosfet diode,?

I’ve tested the components and they are all ok. At least the diode, mosfet and the SCR.

Could you verify the value of r49 with me? Blue/grey/silver/gold?
I have it as 0.68 ohm? 5%. 1 watt
reading a fluctuating open for me.

 

Yes. 0.68Ω .

 

Yes. 0.68Ω .

Thanks!!
I’m going to reference this thread here where it was you that mentioned r49 was 68 ohm.

https://forum.allaboutcircuits.com/threads/mc2100lts-30-treadmill-repair.186416/


R51 for me was vaporized but I replaced it as an 18 ohm resistor. Could you double check for me that it truly is an 18 ohm?
Much appreciated!! Thanks

 

My previous older post on R49 was obviously wrong for some reason.
R51 shows and measures 18Ω, i.e. Brown, Grey, Blk

 

Thank you so much!!