Bachmann DC DD40X Diesel Union Pacific 41-0665 horn sound repair

[michaeld4502]

I recently bought this loco 2nd hand. The loco runs, the blinking Led works and the light bulbs, but it has a horn sound and it doesn't work.
Would anyone know how it supposed to work ?
I suspect one the components on the "Space Age Electronics" on the PCB maybe faulty.
I connected 5VDC to horn and it makes a sound, just not while it's on track.
Would anyone have circuit diagram for part no.3102 ?

[Trainman203]

Second hand engines ...... "Buyer beware!"😮😱. (Repeat 100 times).

[Len]

Your description sounds like the 4-wheel drive 'pancake' motor version from the 80's.

About the only good thing that could be said about it is, it made the 4' x 8' layout world happy because it would go around 18" radius curves. Of course the overhang was rediculous, to the point of knocking buildings off the table and smashing tunnel portals.

You'd need to trace out the PCB and make your own schematic if you really want to trouble shoot the board. But it's probably not worth the effort. Even if you do, the bad component may not even be made anymore.

Len