I've done the video on the Revox recorders - Different speeds, 2 and 4 track and dates going back to 1963. One is even a tube recorder. The audio files are available if you want to follow on. Wav files here
The second video was certainly an eye opener! They always said that electronic devices stop working when you let the smoke out. I guess that proves it.
The smell is more like burnt insulation - and it was doing odd things just before. It recorded, but there was no replay? The tape was fine and played back on another machine to confirm recording happens, but no meters and no audio. I'll pull it apart when I get a moment.
MISTAKE
Rich has pointed out I made a mistake in the recordings and I've confirmed he is right - The Revox G36 was in MONO! Here is the link to the stereo file. G36 Stereo