The prodigy advance seems to be working properly I think.
I have the same voltage at the PCB no voltage drop. Got one train working sort of. Stop n start but not full steam. I am 99% sure the issues decoders or motor.
Thinks for the help.
I think that it is probably dirty track and/or dirty wheels.
For reliable operation, track needs to be very clean and wheels need to be very clean. Stop and start/stuttering operation is a classic symptom of dirty track and dirty wheels.
Get a track rubber and polish the track. If you don't have a rubber, use metho and paper towel and polish the track. The rails should be "bright" when clean. Once the track is clean, examine the wheels. Each wheel should be "bright" and shiny across the wheel tread. If there is dark crusty material on the wheel treads and onto the flange, carefully remove it. Metho and paper towel is best. Avoid using something sharp to scrape crud off. The small scratches then become a place for crud to build up.
A good method is to apply power to the track. Apply Metho to make a paper towel damp and place on the track. Place the loco with half of the powered wheels on the paper towel and the other half on the rails. Hold the loco in place and let the wheels revolve on the metho/paper towel. Clean half the wheels, then clean the other half.
For any DCC setup, you should also have a DC test track. If a loco doesn't work well on DC, it won't work any better on DCC! I always
test on DC first before doing DCC work. The paper towel on track is probably best done on a DC test track.
An important thing is to not run rolling stock with plastic wheels on your layout. Plastic wheels leads to crud on your loco driving wheels. All of my rollingstock have metal wheels, any plastic wheels get removed and cast aside.
Good luck, clean as best you can and see what happens then. The MRC is probably the pick of the controllers.