I was setting up the LIONEL 8370/71/72 set and noticed I was getting a sparking from the B-unit near the pickup - a little more than I could ignore.
A few times around and it was getting worse and finally tripped the breaker on my old ZW...alas a un-ungraded unit. (or seemed to - the train stopped)
I thought maybe something derailed.
A few seconds later I noticed smoke coming from the B-unit...pretty stinky!
Further study showed sparks jumping from the couplers to the ladder when the little coupler spring tips touched the ladders when rounding a 027 curve.
Opened up the car - the small horn circuit board is held in place by a piece of double sided foam tape - about 1/4 inch thick. The foam is supposed to keep the circuit board in place.
Well, at some point the board got loose and shifted to one side - and off the tape and onto the metal frame - just bouncing around in there.
The vibration of the train made electrical contact with the back of the board - causing the sparks I was seeing in tight curves were burning that board up...I think its fried. I was planning on putting some other kind of sound system in this car - so no great loss if this is burnt.
But - for sure, my fault for using the old ZW with something that could (literally!) burn up...a lesson in safety for sure.
For whatever reason, I assumed these had a post-war style horn in them - and not a little soundboard/speaker. (on the box, its called an "Electronic Diesel Horn")
But more of a warning about the way that horn circuit board is affixed - something I will always check when running these horn-equipped MPC B-Units in the future.
Way too easy for that board to get loose from the adhesive foam strip.
I'd especially check this if I were receiving one of these in the mail - or after storage.
I'm sure I'm not the first one to have this happen - probably a known issue - but I figured it couldn't hurt to mention.
