Most likely the belt. The lower deck has 3 belts. Two that operate the deck and one that operates the counter and the Tape Run indicator. The reason the Tape Run indicator ran for 2 seconds then stopped is because that is exactly how long it took for the old stiff belt to travel from the larger pulley of the counter to the smaller pulley on the right spindle wheel. Now if your counter is working but the Tape Run indicator isn't, then you have a bigger issue. Usually means the contacts are bad/dirty or a mechanical issue with the power distribution box that governs the LEDs.
However, if the counter isn't working its the belt. To verify pop open the door. The eject latch that moves up and down with the eject button is on the right and the Tape Run / Counter belt runs between it. Press FF on the deck and watch that belt. If it doesn't move then there is your culprit. SBS8.9 is the belt size (SBS8.9-9.2 sizes will work also).
P.S. - You can replace this belt without taking the whole chassis out but be prepared to cuss and have something to take your frustrations out on near by. The lower cassette deck circuit board does need to be loosened and moved out of the way. You can pull the belt out from around the right spindle hole. From start to finish takes 15 minutes if everything falls into place. Takes an hour if it wants to be a PITA.
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