Interesting, if the board was bad, I would think the audio cast from the player wouldn't work all.
I have had several of those IR lock-ons go bad to produce some very erratic result from any engine placed on the track. That Lock-on should be able to shut the power off to the track, and if it is producing "dirty" power to the track it can cause these erratic results. The one Loco-Sound engine of mine that works is very picky about its power source. It would make the same static sound you heard with the IR lock-on and then work perfectly from a known good transformer.
