Please help me troubleshoot MPC era GP9

It sounds like the E-unit is hung up.  Did you check to see that the plunger is moveable, up and down and the little barrel rotates?

.....

Dennis

First, check all the wiring and make sure it's still attached.  Like the post above noted, make sure the drum is rotating in the reverse.  A likely culprit would be the fingers on the drum in your reverse unit need to be carefully readjusted.  Remove the shell, and attach test leads to the engine - alligator clips on a roller and a wheel on the non-motor truck would be good spots for this.  With the engine off the track apply power and watch the drum rotate.  Carefully take the eraser end of a pencil and apply light pressure to the fingers across the bottom of the drum.  Remove the pencil, cycle the reverse unit and apply the light pressure to all the fingers.  You'll most likely find that the fingers need to be bent downward slightly to make proper contact.

Something else is at play here as neither explains why the lights do not come on when powered up on the track.

OK, this morning I took a "bigger hammer" approach and gunned the throttle.  Loco came back to life.  It took about 5 minutes of cycling to restore the reverse.  So it works again.

The only thing funny now is that when in reverse, going through a 90 degree curve (2 sections of O27), the loco buzzes loud, but not in forward.  Do I need to check the e-unit again, or is is time to play with the set screw on top of the motor shaft in the brush plate?

There should be just enough play in the armature that you can see it move up and down slightly. A Small dab of lube is also needed on the shaft inside the brush holder. Turn the screw down till the armature won't rotate, then back it off just a tad.

Rob is correct the lights should come on even if nothing else works...Jim

OK, I think it's fixed.  Took it all apart again.  Played with the set screw and think I have it adjusted as close as I can get.  For some reason, it seems run smoother in reverse, but I think it's as good as it will get.  I think the lamp was an unrelated problem.

Thanks to all for the assist.

If the brushes check out as being OK and not worn on an angle, and it runs faster in one direction than the other, the brush springs need either replaced or just adjusted. While under power, push in on each brush with a pencil and see if it speeds up. You then rebend the spring that speeds it up to put more tension on the brush.

Your #8759 Diesel, I believe is the Erie Lackawanna. Always thought this was a sharp looking diesel. 

OK, revisiting this GP9.  After the holidays, I replaced the brushes and the brush springs.  The original brushes were worn at an angle.  I played around with shimming the plastic brush plate a bit so the rpms seem about the same in either direction (didn't put a tachometer on it, just went by sound).

When turning the wheels by hand, they go easily in one direction (reverse).  But when I try to turn by hand in the opposite direction (forward), it's very difficult.  But when I power it, it runs ok.  Gears look fine, and were cleaned & lubed.

Now, I have the e-unit lever in the off position, so it will just run forward.  It runs well, except for every so often, after a stop, it won't move.  It may happen once every 3 or 4 stops (or pauses with the direction button on my KW).  It'll light up, but won't go without a bump or push.  Any ideas on what could be wrong?

Thanks,

Chris