MTH PS3 SD45 stutters sometimes - need help!!

My son has the same model and is experiencing a stuttering at slow speed on level track.  It's still under warranty so he's taking it in to a dealer to get examined.

Ron

It might be a tach board problem or striped tach reader reads stripe is not in good shape! check your tach strip on flywheel and check condition ?

Alan

Make sure you’re applying at LEAST 18 volts to the track for power or you will experience similar issues.

Thanks to everyone for the help, especially Mr. Jeff Sohn.

Turns out it was the power!

-John M

Glad to hear it was an easy fix for you.  My Son dropped his off at Nicholas Smith.  They are guessing it could be the tac tape or tac reader.  Estimated 3 weeks. 

Ron

@John m 43 posted:

Hi everyone,

i recently bought the new MTH PS3 Maryland Midland SD45 #3449, and I've been having some trouble.
I got it today and tried running it on my layout, and it worked great on my 0-36 FasTrack curves. It's my first high-end loco and I really enjoy it - especially because the real thing runs near my house!
However, it wont go up my grade. It's 4%, which is steep, but that doesn't seem to be the problem. It just stops sometimes on it, past halfway up. The power stays on in the engine, and all the sounds stay, and I can make it go backwards, but once it stops, it wont go forward again.
My only thought is that I don't have enough power supplied to the track, so it stops because of the power required for the grade - as if it is automatically preventing a short circuit or something. The power pack I am putting into my DCS explorer is maybe 2.5 amps tops.

Curious what the track voltage was at when it wouldn't make it up the grade. Was that pulling a train? Or by itself?

@BobbyD posted:

Curious what the track voltage was at when it wouldn't make it up the grade. Was that pulling a train? Or by itself?

I believe it was under 9 volts, probably around 6. And yeah, just by itself.

@Ron045 that sounds terrible. I hope it works out and the fix isn't too expensive for you!

I can run a PS3 loco on less than 16V under DCC since I turn off the smoke units on all of my MTH trains.

According to the DCS manuals, the only thing that the voltage limits in command mode is top speed.  Of course that’s probably within reason.  I’m not sure if the circuitry is such that it’s regulated constant power, where as voltage drops, current draw is increased.

Under 9V is pretty low for DCS operation without reserve for speed control.  Not sure why tach reader would be a stutter issue, especially if it can maintain speed control.  Stuttering would seem to be a gear train issue in my mind were it is seeing some extra resistance.  Side gears wobble or debris, maybe worm gear break in.  Especially if your at a decent speed.  Crawling yes maybe, but track power pickup can effect that too.  G