Re: Jem77p-bfp tremolo upgrade
Here are some things that can cause tuning issues with the Edge trems(in no particular order):
1-Adjusting the post height and not first loosening the locking screw(small allen screw that is down in the center hole). Not all Edge posts have this, but if yours does, its important to loosen or you might break the large allen head(these parts are replaceable with Ibanez Rules being a great source). Once height is set, tightening this screw creates a very solid connection from bridge to body.
2-Adjusting the posts with full string tension; this will eventually wear both the knife edge of the trem and the V-shaped part of the post. As those 2 parts wear, they will not always go back to pitch.
3-Brand of strings. Sometimes changing brands will make the difference. For me, Dean Markley seems to hold tune a bit better than D'Addario.(no idea why)
4-stretching the strings(already mentioned)
5- A locking nut that is either not tightly locked, or has loose bolts in the neck. I have seen a few where the locking nut actually moves when the trem is lowered and then returns.
6-Bridge not setup correctly. At rest, the baseplate of the bridge should be level with the top of the body. To set that, I will tighten the springs(or add more), block the bridge so it stops when at the correct level, Tune to pitch and lock the nut, remove the block(the guitar will go way sharp), loosen the spring claw(remove extra springs) evenly on each side until the guitar is back in correct tune. Changing string brands, composition or gauge can all require this to be reset.
So, if your guitar is not staying in tune, something is amiss. I tend to abuse mine a fair amount and rarely have tuning issues. For me, the original Edge, Edge LoPro and Edge Pro are the best trem bridges ever(Edge Pro 2, Edge III and the like, not so much). One of my guitars is an RGT42-DR and I replaced all the Korean hardware with stuff from the Prestige line and its every bit as good as the J-Custom I sold last year.