Spectrum 2-8-0 stops and starts randomly

[teddavis07]

Hi Everybody,
I have this Spectrum 2-8-0 that came in a nice black box that says 'DCC sound on board'.  This loco came installed with a Tsunami 16 bit sound decoder. I've had it for awhile and just last week decided to take it out of the box and test it out.  Called it up on address 3, checked the functions and started running it.  It began to stop and start randomly at any speed.  I'm using CVP's EasyDCC system.  Next, I decided to check out the CV's with Decoder Pro with my computer and using my Sprog II decoder programmer.  I tried tweaking some settings, testing it again, and found that it runs fine with Sprog II decoder programmer system.  When I move the loco over to the layout, using EasyDCC, it starts this random stop and start motion again as it rolls down the track.  The track is clean too. I've taken the locomotive apart, lubed it, checked the decoder in the tender and cannot see anything obvious to fix.  The other posts I've looked at appear to be referring to the earlier models that were made with capacitors you could clip, but this unit does not have those capacitors.
Suggestions?

Thanks, Ted

[richg]

Have you actually cleaned the track or does it just look clean?

Rich

[teddavis07]

Yes, I cleaned the track as soon as I noticed this stopping and starting motion.  It is very random where it chooses to do this.  It can be moving very slowly or moving a scale 40 mph.  The sound continues to play but the loco hesitates and then continues to move.  When I had the loco apart, I noticed that all 8 wheels have wipers on them for electrical pick-up and the tender has wipers on both trucks as well.

[wjstix]

One thing to try if the engine has the "apron" that folds down between the cab and the front of the tender:

Fold up the apron so it's sticking straight up. Then put the engine and tender on the track. When you're sure all the wheels are on the track, reach in with a small screwdriver or pencil etc. and lower the apron onto the front of the tender deck.

There's usually a "lip" on the front of the tender, and that apron easily gets stuck underneath it, which raises up the engine and causes conductivity problems.

Also: try running the engine very slowly and see if it "sticks" at any particular spot in the rotation of the drivers. I've had a couple of Spectrum engines where the siderods got bent during the long trip in the box from China, and are bent in enough to foul one of the other rods or clip something else every rotation. If that looks to be the case, you can carefully bend the rods out a little.

[richg]

The caps are on the board somewhere. They will be on the Bachmann PC board that the decoder plugs into. They will be labelled. C1, C2, etc but I suspect it is not the caps causing this.
How does another loco work on the layout?

Rich

[teddavis07]

The apron is in the down position against the cab and not interfering with the motion of the loco. The side rods turn without interference. While watching the side rods, it was again random where it would suddenly stop and then continue. The sound output reflects this sudden stop by playing the appropriate sounds. My other locos are running fine. I have both steam and diesels running.  If they do stop, it is because of dirty track and sound and motor both cut out until I actually move the loco to clear the dead spot and clean the track. This is the only 2-8-0 I have, so I'm unable to replicate the problem. 
The green board's electronics are very small, unlike the pics I've seen in other posts.
Any other ideas? Thanks, Ted

[Doneldon]

Ted-

Try turning your loco over on a safe surface and then apply DCC system power directly to the wheels. Does the loco work OK when you do this or does it continue the start/stop crappola? Try different combinations of left and right wheels on the engine and tender to see if all wheels which should be picking up power are doing so. Also, does your sound system start over with the powering up sequence after the loco stalls and restarts or do you just have an interruption in the sound without a fresh start? Please share your answers to these questions and we'll try to go to the next level with you.
                                                                                                                                                                               -- D

[teddavis07]

What is the procedure for connecting the loco.  The wheels are all rod driven, so attach clips to the wipers next to the drivers and then connect the tender's two trucks?
I'll do a continuity check on each wiper as well.

When the 2-8-0 intermittently stops and starts, the sound is interrupted without a fresh start.

[Doneldon]

Ted-

Just hold the wires against the tread of the wheels. You wouldn't want to do this long-term because you can get some small pits from arcing but it's worth the risk of that to get a good diagnosis.

The fact that your sound doesn't restart suggests that your power is uninterrupted. This probably indicates an intermittent loss of power to the motor without a concomitant interruption to the power to the decoder. Now we're zeroing in on the problem.
                                                                                                                                                                                -- D

[Irbricksceo]

a Few questions:

1. Have you tried resetting the decoder, just in case.
2. When it stops, do  you still hear the motor turning, if so the problem could be the worm failing to catch the gear on the axle.
3. Does the DCC system say a short has occured when it stops?
4. How long are the periods of time it stops for.

[HDiedrichs]

Are the wheels out of alignment. Some of those get an alignment issue problem. If the wheels are not perfectly 90 degrees on either side the loco will bind and stop.

[bapguy]

Look at the wires between the tender and loco. I had a similar problem and found the wires were causing the front tender truck to loose contact. I separated the tender from the draw bar and gently spread them apart to straighten the wire out. I let it sit this way for a couple of days before replacing the tender to the draw bar. The wires should have a nice droop to them.  Joe

[electrical whiz kid]

I have a 2-8-0 with that same problem.  I took it out of service, and when I find the time, I will call Bachmann and go from there.  I thought it rather odd the behavior-but maybe it isn't.
Rich C

[Jerrys HO]

Just a thought as I read this thread when someone responds and find this interesting and thought I would share.
About a year ago I purchased two Digitrax decoders to replace the Bachmann decoders in my SD45's and they ran fine for some time. I started to notice one engine hesitating.
Clean track,clean wheels,what next? I removed the shell and placed the loco back on the track and when it hesitated and stalled I wiggled the decoder to see if it was loose and off the loco went.
Could not be that easy right.... right.
To make this long story short one of the wires had loosened from the socket causing it to hesitate.
You may have a loose wire on the decoder.

Jerry

[teddavis07]

After laying the loco on its side I checked for continuity and found that the tender's trucks are used to pick-up power from the rails.  The wheels on the loco are driven by the motor only and the axles are not insulated from each other so my multimeter sang when I touched each from side to side.  There are wipers on those wheels, but I haven't checked to see what for.  So then I placed alligator clips on the tender's axles, front and rear, and it started right up with sound.  I called up the loco # on the handheld and throttled it up and the wheels on the loco began to turn and the same problem occurred as if it were actually on the track...random stopping and starting. This is a micro second of stopping and then it continues on as if nothing has happened at the current throttle setting.  When it stops, the sound output reacts as though I have throttled down and then returns to chuffing at the current throttle setting.  The Tsunami board actually runs everything.  I disconnected it from the other board and when I gave it power, nothing happened.  I might try putting the dummy plugs in and run it on DC just to see if the same problem occurs.  I will also look to see if I have another sound board I can try and see if the same stuttering and stopping occurs with it.  Earlier I thought maybe the gears may not be meshing properly, but I disassembled the loco, lubed it, and reassembled it and it still had the same issue.  My Valentine is calling, I will get back to this on Saturday.
Oh, and thanks for all the ideas.  I will look at each for possible solutions.
Talk you tomorrow, Ted