I have a Stewart/Kato new FT A with B dummy on a drawbar that stalls/shorts out on several of my Atlas snap switches then starts up…with the Soundtraxx LC diesel decoder.
None of my other locos have a problem on these turnouts and I know these stupid LCs can be a problem. I do not have a stay alive capacitor installed on the decoder. Do you think this would help?
There seems nothing physically wrong with the loco. The wheels are clean. The wheels are in gauge. And I can see no physical problem as the loco passes over the switch. The rear truck is a bit restricted in its turning because the brake cylinders hit the shell foot rail at that point. But it doesn’t seem that restricted. I guess I could pull off the detail and see if that is the problem.
I just think it is these fussy decoders from Soundtraxx which have given me problems like this before.
See if the front and rear trucks are both picking up electricity. If you have a truck that isnt, then it would behave as you have described. Fix the problem with the truck movement. Check to make sure that the brake cylinder is pressed all the way in.
Take the momentum off of the Sountraxx Decoder (CV 3 and 4 set to 0). The big downside to the LC series of decoders is just the issue you have described, they have no way to negotiate dirty, or non-electrical track (isolated frogs). Unfortunately, with the LC series of decoders, there is not perscribed way of installing a cap.
Upgrade your decoder. Look at the Recent Tsunami offerings or the new QSI offerings. They have caps (expecially the QSI Revolution) that help with dirty track. IMHO, both are fine sound decoders, buy QSI has a better drive to it (not to mention more light outputs, no resistors needed for LEDs and a true BEMF).
Take the momentum off of the Sountraxx Decoder (CV 3 and 4 set to 0). The big downside to the LC series of decoders is just the issue you have described, they have no way to negotiate dirty, or non-electrical track (isolated frogs). Unfortunately, with the LC series of decoders, there is not perscribed way of installing a cap.
Is this HO scale? If so I doubt an FT unit has a Kato drive, but if it really does my comments don’t apply. All the Stewart FTs I have (about 40 sets) get power off the axles with a brass plate that connects between the wheel and the outside frame. If these have gotten dirty it doesn’t matter how clean the wheels are. I’ve also noticed that sometimes they don’t make good contact because they have torqued slightly during assembly. I use electrically conductive lubricant on them (right on the axle).
Then a question. Is it stalling because it shorts first? Or did you say stall/short because you didn’t know which? A tiny short could very well cause this behavior in a Soundtraxx LC.
Also make certain the truck has some forward-to-back rocking. I have found some of them are too stiff.
Snap-switches are very tight. That would be an excellent quick and cheap thing to test. If it is the problem you could just cut a small knotch in the cylinder to give it a bit more clearance.
I also have many (most) FT AB sets where I’ve run two wires for power from the B unit up to the A. That gives 16 wheels collecting power instead of just 8.
Thanks for all the info so far guys (and good link to stay alive capacitors in various decoders. I am going to look into that further.)
Yes, it is an HO FT with Kato drive.
It probably does not short out, but rather loses a connection running through a snap switch on the main rail, but will restart and continue.
And on one snap switch it loses connection and comes to a complete stop while moving from the mainline to the siding (occurs to me there is proper terminology for a loco running through an unthrown switch and through a thrown one, but I don’t know what it is.)
And when it does come to a complete stop it can be brouight back into contact by rocking it on its trucks. Therefore I think the idea of a poor pickup in the truck is a likely problem. I will check that next, because the locos wheels are all still properly on the right rails when it moves through any switch. I bet something is twisting out of contact alright. Hope so.
Oh, yes, I have actually put the decoder and speakers in the B unit and run just track and motor wires back to it from the A unit (hence the drawbar as these will always be together). And all 16 wheels are picking up current very well.
Yes, I used the pickups already in the dummy’s trucks to add more power points.
Yes, the frogs all have drop feeders.
Good news ( I created another post just about conducta lube in which I copied this info) is that I stripped the wheelsets and pickups down to the wire and cleaned and polished everything really well. I also noted that the pick ups are wires pinched in large versions of the plastic cap connecter rather than actually soldered to the brass pickups. I took these off and repositioned the wires and reassembled and the unit seems very smooth running now. Just a little loss of contact makes those stupid LCs act up.
Make sure the electrical pick up wires to the wheels aren’t shorting out on the frame. Some manufactureres use a plastic cover near the wheels to hold the wire to the pickup. These can come off causing the pickup wire to short to the frame. It acts like it is stalling especially on turnouts. Ask me how I know [banghead]