So here is the offending part (640-8112-116).
Those four bipolar transistors over in the lower left are what got hot. The E-unit is mounted to the frame using a C-shaped metal bracket. The board is then mounted to the bracket using two bolts and nuts with insulating washers slotted through the eyelets of each transistor pair. Additional insulation is provided by 4 extremely thin clear plastic films. Not sure if one or more transistors failed, if the insulating washers failed or maybe one of the thin films. Potentially one or more transistors got hot enough to compromise the board soldering based on what I can see with my readers on.
In any case, my poor #170 won't run. I tested other components... Lamp, good. RS-385SH DC can motors, good. RailSounds components, great! Thinking of giving the fore mentioned Dallee E-unit a shot as it should be a pretty easy drop-in replacement. Anyone know which of the three products on Dallee web site (#400, #518, #1400) would be correct for a 2002 Lionel EMD FT Diesel with RailSounds? According to the site, #1400 seems to be the one size fits all, but it also seems to be a lot larger than the other two models and potentially overkill for this engine. Since I intend to leave the original RailSounds components in, mounting space could be at a premium.
Other suggestions?
