Sound is very wobbly.  The ffwd works, but the rew doesn't. Any ideas on a remedy?  Changing the belt maybe?

Yes, most likely it is the belt.

More unlikely reason is dried up lubricant.

Neat.  I have to figure out how to get this thing opened now.

Finally got around to getting this thing opened.  Only way I could get the belt replaced was disconnecting the battery wires.  So fresh new belt is in... but this thing is so tiny I'm not sure if I could get the wires resoldered without melting some other things.

Any tips?

I really want to know how people put these together because it's ridiculous how much they've crammed into this thing.

Hey doober314,

Did you ever resolve the wobbly sound with your JJ-P5?

If not fixed you may try the pinch roller assembly. If the rubber roller is shiny that's an indication that the rubber is drying up and getting hard or that tape material has found its way onto the roller making it slick in that spot.

You can find a rubber cleaner/conditioner that will help restore the roller in its early stages (if it has small cracks don't even bother just get a new one). I apply (while in play mode) to the roller using q-tips. I continue to apply cleaner until little or no black residue is found on the q-tip. DO NOT use rubbing alcohol unless it is 90% alcohol. Most are only 70% and contain other ingredients which will further dry out the roller. Use alcohol on head and tape paths only.

The Brand of the cleaner is TASCAM (a division of TEAC) part number RC-2. it comes in a 7oz can and will last you forever. Recommended cleaning is every 6 hrs of playing time.

The pinch roller assembly governs the tape speed across the head. If it is getting hard it will slip causing flutter (a wobbly sound) 

If after cleaning the roller it is still shiny you can use a fingernail file to help try and restore it somewhat (although this is a temporary fix). I borrow from my wife without her knowing. Open the door and press play. As the wheel turns (evenly and LIGHTLY) apply the file to the roller until the shine is gone. Don't over do it or you may make the problem worse. Then use the cleaner. If you are having to go through this measure to restore sound quality, your best bet is to start looking for a place to order you a new roller.

Outside of a belt which was mentioned earlier it could be head alignment (causing tape drag) or slightly bent capstan (rare). If reverse failed at the same time it started sounding funny then I would definitely suspect belt as well.

Cool! Thank you very much for the advice.