proto 2000 GP9 power issues

Model Railroader General Discussion (Model Railroader)
1

I’m running a proto 2000 GP9 on DC with a MRC tech 4 power pack, I own 3 of these locomotives, however one seems to take so muich power just to move, nearly 70% on the throtle, i tried cleaning the weels and motor for some reason it got worse, maybee a loose connection to a wire?

2

sometimes when they get put together, the drive wheels bind up. then they dont move easy .that will drive up the current, I have taken a few apart and its not that hard.

Ken

3

Besides any mechanical as Ken mentions, there could also be issues with the “new” motor itself. Have you actually run them in through a good hard break-in period? Generally this is not an issue with most of the newer equipment, but a new loco may need some run time and break-in to loosen it up. Many years ago, I especially noticed this with Athearn BB locos. Even pairs well broken in would need some run time to almost break them in again and to quiet them down after many months or years of sitting in a box.

4

If your units are more than 6-7 years old, the geared axles have probably developed hairline cracks that causes them to bind. (It was a brief problem Proto had with some 4-axle units, but definitely the GP7’s and 9’s.) Contact Walthers for replacement axles.

Cheers, Marty on Vancouver Island

5

Shawn,

You could have an electrical or a mechanical issue. Diagnosing which is the key.

Remove the body and check the following:

  • I am sure you lubricated all necessary points already but it bears mentioning.
  • These were known for cracked wheel set gears so check those also.
  • Run the unit without the shell. Is anything dragging on the drive shafts?
  • Now disconnect the drive shafts. Compare the effort to turn the front and rear trucks. Is it equal or is one excessive? Compare to one of the known good units.
  • Do you have a DMM? Set it on Ohms and check the wiring from the wheel sets to the circuit board. You may not be getting sufficient current to the motor.
  • Check the motor. I know the motor is buried in under the weight, but it may be the problem. How are the brushes and the area where they touch the armature?
  • The pole windings may be shorted. This will decrease top speed and increase motor temperature. The motor cannot generate a sufficient magnetic field but will draw more current. Before I would condemn the motor, I would swap it into one of the known good units. Did the problem follow to the good unit?
  • If the problem is not excessive drag, the pickup wiring or in the motor it has to be in the circuit board. On my GP 30s the power is routed through this board. Get a magnifying glass and check for “cold” solder joints.

Contact Walthers and they may send you the part you need free.

Jim

6

Check the drive for any binding and lightly oil(one very small drop) the drive shafts,bushings,motor shafts,gears and flywheel shaft.

IF that fails you may have a bad light board…A lot of guys has removed the light board and hard wired the motor and got better running results.

7

Hi,

I would bet the railroad that you have a unit with the “broken” drive axle(s) that plagued the early proto units. Out of the nine that I have, all had at least one that was broken.

There are other threads on this problem, but to simplify things, do the following…

Turn the loco over and with a small flat blade screwdriver pry each end of the gear cover off. The gear cover is a black plastic piece about 1/2 by 3 inches located between the wheeels on each truck.

Pull out each of the wheelsets. If you can EASILY twist one wheel in relationship to the wheel on the other side of the axle, IT IS BROKEN. Then, check all your Geeps for this.

The good news is that Walthers will happily supply you with a FREE “repair kit”, which is a set of new axles. Give them a call (check your papers that came with the unit) and they will gladly be of help. Frankly, the folks at Walthers are about the best I have ever dealt with - except maybe those at Kalmbach.

ENJOY,

Mobilman44

8

The unit in question has already had it’s axles and weels replaced for free from walthers so I know thats not the issue, neither is thier any binding occuring, i beleive it’s an eelctrical problem with the motor or the light board, at this point i havn’t tracked down the problem… yet.

9

My money’s on the light board. I’ve had issues with them before.

10

Shaun, I have a ton of those plug in boards, PM me your address and I’ll send you some if you need them.