Marantz 5030B slooowing down- needs new belt?

[happythecat]

My Marantz 5030B cassette deck is all original. Nothing has been replaced; the heads were always cleaned and demagnetized. Last week it played great, then this past weekend when a tape was inserted it slowed down for a few seconds and then kicked into normal speed. Now when a tape is inserted it plays very, very slow. Rewind is slow; fast forward is fast.

After 30+ years it probably needs a new belt. Is it difficult to replace the belt? There are a bunch of screws on the sides and bottom of the case; I'm not sure which screws to remove.

Do you have any suggestions?
Is the 5030B worth fixing?

 

[Strawman]

The 5030 looks like a nice deck. As you stated, it's all original. I would think that a belt kit would be in order. I wouldn't touch the screws on the bottim yet, usually just the ones on the side, & maybe the top or back will hold the cover on, then you can see what you're up against.
Some models will require the entire transport to be removed/diassembled to replace the belts, others may allow just a few parts removed to gain access to the pulleys.