K-Line TMCC Couplers firing randomly

Classic Toy Trains Forum
1

I have two K-Line TMCC equipped locos… the small Big Boy and a Dreyfus Hudson. The electo-couplers on them tend to randomly fire open when they go through an insulated rail section especially non derailing switches. I’ve tried leveling out my switches with the entry and exit trackage and the Locos run through them prety smoothly with a minimum of bumping and thumping but the couplers still randomly fire open. I don’t seem to have this problem on my Lionel TMCC locos. The K-Line Tenders have a pretty cheesy center roller attachment and I was thinking that the center roller contact might be inconsistent and causing the problem. Anybody know what causes this random firing problem or how to fix it?

PS. I’m not an electronics expert. I do OK with electro-magnetic circuits put electronics bewilder me. (Maybe I should just stick to post war)

2

I had this problem with a K-Line and the repairman found a short inside the tender.

3

You might want to ask this question on the TMCC forum. I remember some discussion on this. I think the cure was adding a capacitor but not sure about size or location.

4

Jfarrey - install a 1 uf (microfarrid) non-polar capacitor between the 2 wires going to the coupler. Radio Shack # 272-996 ; 1 uf; non-polar; 50V max.

This was/is not an uncommon problem. I believe it is due to a false signal being generated with certain track conditions when the engine passes over the area.

5

Thank you so much for the reply. I’ll give it a try. I’d heard about using a capacitor but given my limited electronics knowledge, could never figure out what size to use. Thanks again