Surging P2K GP30

Model Railroader General Discussion (Model Railroader)
1

I have a pretty new GP30 that runs terribly. Its speed varies badly when running at very low speeds. I checked the wheels (in gauge, not bent, making good electrical contact) and the axle gears. What would be the likely cause of this? I assume it might have something to do with the worm or the gear that the worm meshes with.

Any comments from experienced P2K owners?

george

2

Does it make any clicking or occasional clucking noise as it runs? A cracked gear sounds like a flat spot on a wheel tread.
Bob K.

3

You say new GP30…are you sure it’s new?It could have been on the shelf for years. I just got one and had the same problem plus cracked axles. I thought it was just the axles. That helped but it still surged. If the light flickers then you still have poor contact. I eventually looked at the wheels and they were corroded. This is just surface corrosion. After I cleaned them with my wire brass brush wheel cleaner til they shone it ran great. So check that out and hopefully it will solve your problem.

4

Balantrae Road has the right idea, particularly if you are running DC. If you are running DCC there may be other issues.

5

I would refrain from cleaning your wheels with a wire brush. This creates scratches in the wheel, which gives dirt a place to accumulate. Since you’re going to disassemble the trucks to check the axles/gears, I would clean the wheels with a cotton rag and some alcohol.

6

My P2K U28b has some issues as well. It just shuts down by itself in DCC for a second or two and then comes back. I wont be purchasing P2K ever again.

7

The axle gears are definitely OK, and the wheels look good. There is no problem with conductivity. After all this thing has a soundtrax DSD - LC in it and as we all know, those decoders are intolerant of connectivity problems. That’s why I’m thinking it is in the gears someplace. I will have to pull the gear towers apart I guess.

And I don’t hear any chicken-like noises coming from it either so I’m thinking that none of the gears are cracked (not just the axle gears).

g

8

I assume you’re running DCC… one thing I’m always suspicious of with “surging” is that you may have two throttles talking to the loco at the same time… sending conflicting data.