Stuttering Walthers Proto F7


B

btk

New Member
The pride and joy of our fleet, a Walthers Proto Alaska F7A, stutters quite a bit. It didn't always do this. The embedded video is of the loco running over two sections of Atlas code 100 flex track, each of which has a feeder soldered to it (you can see the feeders on each side of the rail joint at about 0:09 in the video).

[YOUTUBE]le67F4HK4N8[/YOUTUBE]

The track is clean and I've cleaned the loco wheels with rubbing alcohol and one of those wire brush things that attaches to the tracks. No black gunk comes off of the wheels anymore.

I've checked all combinations of all four wheels on each side for continuity (1-2, 1-3, 1-4, 2-3, 2-4, 3-4) and they all pass.

Where do I go next? Is there anything else I can do to troubleshoot it, or does it need to go back to the factory? And will Walthers even still look at it if I've already popped it open and fiddled inside?

Thanks!
 
Just a few ideas:

- Have you run another DCC locomotive over the same tracks to see how it reacts?

- Have you check to se if the wheels are in gauge?

- Have you check the track to see if that is also in gauge?

Greg
 
Other DCC locos are fine around the same track.

I haven't checked the gauge of the wheels/track yet. Will do that tonight and report back.
 
I have one sound DCC loco that runs great...but park it over night and the next day it needs a push to get it going. Once running I can stop it and start countless times.

Greg
 
Forgot to ask, does this happen at the same spot every time? Which DCC system do you have? The loco could be under the control of two throttles.

Greg
 
It doesn't appear to be in the same spots each time. We're using a Digitrax Zephyr Xtra.

I am pretty confident I can say that it's not a multiple throttle problem as it's been doing this consistently for a while. Even if it was a throttle issue, I don't think that would cause the sound to cut out and restart, would it?
 
btk said:
a Walthers Proto Alaska F7A, stutters quite a bit. It didn't always do this. ....

Where do I go next? Is there anything else I can do to troubleshoot it, or does it need to go back to the factory?
Click to expand...
I do not recall the power pick up scenario on the Proto F units. I don't remember if those have a bearing on the axle or a wiper? Perhaps the power pick ups are dirty? If it is a wiper clean the back part that wipes on tire or axle with a thin swab. If it is a "bearing over the axle" perhaps applying an electrically conductive oil will help.

Have you cleaned the insides of the rails or just the top?

It is hesitating on the same solid piece of rail so I think that eliminates the possibility of any feeder to track issues.
 
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I am not into DCC, but it does sound like a bad connection or a cold solder joint. I do have a couple of DCC locomotives with sound and if I haven't run trains for a while, the least but of dirt on the track will give the same exact symptoms you have, but you have cleaned the track and other locomotives don't have a problem. I would check the connections, starting from the trucks and working to the decoder and the connections to the decoder. Electronics is something I do know well.
 
Thank you all for the suggestions!

The track is clean, on top and inside. The track it's running on in the video is actually brand new track, but it does this all over the layout.

I found my NMRA gauge last night and verified that the track is fine, as are the loco's wheels. I didn't get a chance to pop the shell off to see how the power pickup is done or to check the internal connections. Planning to do that tonight.

I did, however, factory reset the decoder just to eliminate any potential programming issues and the problem still occurs.
 
Since everything is eliminated for a source of the problems, it maybe a bad decoder and needs to be replaced. Return it to your dealer for a replacement or to Walthers.

Greg
 
The trucks themselves look fine to me (photos below for reference and to see if any of you see anything out of sorts with them). Electrical continuity testing within the trucks also indicated no issues.

When I removed the wheels from the trucks, I noticed some "fuzz" wrapped around the axles. On several of the wheels, this fuzz was also making its way inside the bushing that holds the axle in place at each side of the truck. From what I could tell, the power is transferred from the rail to the wheel, down the axle, into this bushing, which then makes contact with the copper pickups on each side of the trucks. Following some quality time with some less-than-quality fine-tipped tweezers, confidence is high that nearly all of this fuzz has been removed. By the time I got everything back together I didn't have a whole lot of time for testing, but initial observations were encouraging. The only stuttering I saw was at the frogs on a couple of my Bachmann EZ-Track sections, which doesn't come as a surprise.

The Jr. Engineer and I will conduct more testing tonight and will report back.

Front Truck:
truck_front_small.jpg


Rear Truck:
truck_rear_small.jpg
 
Question:
If you turn off the sound does it still occur? IF the stuttering stops, there is a good chance that the motor is failing and drawing more amps than the decoder will allow. OR the load protection on the decoder is failing. Cutting out the sound just lightens the load on the decoder.
 
BTW....looks like the gears in the truck have too much gear and lube.

I would take them apart, cleaning the parts with alcohol and sparingly add some lube to the gears and axles. Then check the contacts for electrical pickup.

Keep us posted.

Greg
 
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btk said:
The trucks themselves look fine to me (photos below).
.... From what I could tell, the power is transferred from the rail to the wheel, down the axle, into this bushing, which then makes contact with the copper pickups on each side of the trucks.
Click to expand...
Well, now I know why I could not remember how the Proto picks up power. Despite having bunches of the units, I've never had one apart to look inside the trucks as you have pictured. Thanks for adding to my body of knowledge.

Your description of fuzz is exactly what I had issues with on the old Atlas Roco. They had wipers on the back of the wheel that accumulated massive amounts stuff off the track. I was always having to clean them.

Any further update on your situation?
 
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