It is not the belt as I tried 3 different belts and each time the result is the same. I don’t think the pinch rollers are the issue as they look okay (not hardened nor damaged, etc…). So I am clueless . The mechanism seems to switch correctly while testing with the cover opened (hold the white top switch and the 2 switches near the battery compartment). Then the mechanism switches the the left, runs twice and then switch to the right to run once before it powers off.
Not sure if the right pinch-roller positions itself correctly to the back enough, but the tape eating happens on both sides (depending on how many tape is played OR left from the side it playing).
Another thing I sometimes experience is that during Rewind or Fast Forward, at the end of the tape the gears make a rattling sound although the end of tape is reached. Then it does not stop from the rewind or fast forward action. Similar to the noise when you check a new belt by manually change the black lever position and then manually turn the motor left and right. At a certain point it does the same constant clicking/rattling.
Thanks in advance for any suggestion! By the way, I spoke to another DCC enthusiast (P. Koeleman) who experienced the same/similar issue with his DCC 134).