Error 3 -Reel Trouble Three
"The slack or breaking of the tape is detected in playback mode, or either of the lock of the supply or take-up reel is detected, and then tape protection is done."
Don't you just love Japanese translated into English?
In other words, one of the reel motors wasn't working as it should, either the FG frequency is missing or the motor isn't detecting enough tension on the reel table, so the machine went into the tape protection mode to keep the tape from being damaged.
Could be caused my lots of things. Damaged tape cassette, reel table at an incorrect height or setting, dirt in the motor, bent shaft, or just bad voodoo.