This may have been covered already in another post but I was having problems with the tremelo bridge rising up and not laying flush on my JTV-69S Gen 1 model (no threads on whammy bar). I did some Googling and found a few chat sessions and a couple of You Tube videos that were helpful in pointing in the right direction. That said, I couldn't find anything that described what I did to address the issue so here goes.
To address the issue, I removed the back cover protecting the springs with the guitar strings on (and tuned to pitch). I took the same Phillips screw driver and gently tightened the 2 screws that help hold and position the tremelo until the tremelo bridge lay flat on the guitar. In my case, it took only a little tightening. That was it. Everything seems to be fine now. ðŸ‘ŒðŸ»
I did learn in reading through some forum posts that it may be best to leave the low and high E strings on while changing strings. I typically take all of the strings off and this may have resulted in the Tremelo bridge behaving in the manner it did. Not sure about that but just mentioning it.
Hope this post helps. If anybody has another solution that works, I'm all ears.
Ps: I do have to say that while I'm long time Variax user going back to the very first release, the tremelo on the JTV-69S is mediocre at best. I'm sure Line 6 could have done better with a little more thought. ðŸ¤“