MTH Steam engine wont run.

Seen a few of those earlier models suffer from cold solder joints at the tether connector on the locomotive side....look closely at the solder joints, the tell tale usually looks like and resembles a miniature volcano.....very miniature volcano......Pat

Can they be repaired?

Easily with a fine tip soldering iron, usually all that’s required is a quick re-melt of the existing solder joint.....one trick I’ve done is to put the two together on a piece of track, power it up, and dim the lights in the room, or cut them off, wiggle the wires, and look for the faint tell-tale spark........Pat

What he said.  When I see this symptom, I just touch each joint to the 4-pin connector with my iron and a dab of solder, problem solved.

John,

Can you please tell me or show what soldering iron you use? Thanks.

MELGAR

The approach I have taken is placing a  small dab of flux on each pin using a toothpick and then touching the iron tip.  Sucks the solder right up.

Ron

you usually want a small solder tip as possible and put flux on the pins you want to resolder then when the flux melts is will absorb the solder because you just added flux! flux makes the solder a perfect connection when not enough flux is used or you over heat the joint you will get a cold solder joint and the solder will look dull and like moon craters , evidence of over heating solder joint!

Alan