Unwanted uncoupling-Lionmaster #6-11107 Cab Forward

First step, open the tender and unplug the coupler,  Run it long enough to determine if the problem goes away without the connection.  If it still fails, then it's a mechanical issue, and replacing the coupler is probably the easiest, they're pretty cheap.

If disconnecting the coupler stops the issue, add a 1uf 50V non-polarized cap across the rear coupler leads.  Usually, I put it at the motherboard under the coupler plug, just solder the cap directly across them.

Thanks John!

I'll give it a try.

John-FYI I pulled out the Electrocoupler and replaced it with a standard coupler from my collection of spare parts and all is good. I may just leave the manual coupler in place for the time being.

By the way-when I had the tender off I was shocked by the "swell" in the cast metals sides of the tender. I have heard of "zinc pest" from other forum members, but this is my first experience with it. Will my tender eventually "self-destruct"?

@Don Winslow posted:

By the way-when I had the tender off I was shocked by the "swell" in the cast metals sides of the tender. I have heard of "zinc pest" from other forum members, but this is my first experience with it. Will my tender eventually "self-destruct"?

Yep, sure will!  That's the dead giveaway.  Run it hard now, you'll be looking for a new shell soon.

It's listed as being available from Lima Train Works, I'd suggest checking before they're gone!