Known issues with E-units on certain Santa Fe FT's?

Seems like you probably got a lemon.  I've been using mine frequently on my Christmas display at a local historic theater and it's run fine for the past 5 years other than a wheel that stripped off the axle (still ran well enough to finish off the season last year)

Lemon or not, it's no good to me in its current state.

Any experience with 3rd party E-unit? Some research online turned this up...

http://www.dallee.com/E_Units.htm

Or is it possible my E-unit overheated because there is something else wrong with the engine? I suppose I could put a meter on the can motors to test them out.

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?

Not sure a Dallee unit will allow you to keep the sounds.  I'd upgrade the whole thing with an ERR kit if it was me today.  But as far as going bad, I bought my son one years ago, and it came DOA, actually died on 1st run.  I bought it to give to him for Christmas, and never having run a RTR Railsound engine tried it out while he was at school.  It made it around the track once and started lurching and sounds messed up.  Then it died and wouldn't run at all.  Took 6 months to get the part to fix it as Lionel didn't have any for service.  Needless to say I missed Christmas and his birthday.  It still runs now after the repair.  If he sticks with the hobby, then I'll upgrade it for him in a few years.