MTH Challenger PS2 no speed control

Run8-

Speed control on Proto2 locomotives is handled by a sensor mounted next to the motor flywheel (the flywheel should have an alternating black and white stripe pattern on it). My guess is the sensor is either broken or the gap isn't set properly, which is why the speed control function isn't working. Broken/faulty wire harnesses are a possibility too. I think the flywheel sensor has something to with the chuff rate too, but one of the MTH techs/experts on the forum can confirm this.

-John

I find it surprising that an MTH tech could not track down the problem.  He could/should have posted on this forum and we could have given him specific diagnostic instructions! 

There have been dozens of cases posted here exactly like yours (no speed control on PS2) and to my knowledge every one has been solved...I'd say 95% are caused by what AcelaNYP identified.  The remaining being more obscure failures such as a few components on the PS2 board in the tender which handles the tach signal.

If you're willing/able to open up the engine and inspect the flywheel and sensor area, we can guide you through that.  If you are handy with a voltmeter let us know as that might come into play.  Otherwise, I am absolutely confident some of the guys on this forum could repair it though shipping a Challenger can be, umm, challenging.

And yes, the flywheel sensor absolutely affects the chuffing.  The sound system emits a "chuff" when some number of flywheel stripes passes by the optical sensor.  The number is based on how many "chuffs" per driver wheel you select via DCS (usually 4 per rev).  For articulated engines, the chuffing sequence is obviously a bit more involved but is still based on the flywheel sensor.   So if the sensor is not working, you will definitely lose both speed control and chuffing (and smoke puffing).

Another problem area is the tether.  For a steamer with the boards in the tender, the tach signal and power goes through the tether, any break there and you have warp speed.  The tether is also one of the areas that gets the most abuse and thus is a frequent offender for these kinds of issues.

It can be repaired, period!  That's nothing you've said that suggests this is a major issue.

There is a possibility even your old boards were repairable.  This is pretty simple.  Bad tach reader, bad gap, bad wire to PS-2 board, or bad chip on power supply.  Since you have new boards, it should be one of the others.

If you don't mind mailing it, I can do this repair.  E-mail is in my profile.  G

Why not suggest your "MTH tech" use this forum as a resource and perhaps he'd be willing to take another stab at it for no charge as a professional courtesy or whatever it's called. 

Otherwise, I will endorse GGG for doing the repair though I'd be interested in how much is costs to ship a Challenger coast-to-coast ... twice!