Toilets, Sinks, Showers, Tubs and Disposals - Leak Behind Shower Wall

I've got a Delta ball type shower valve (shower only) about 11 years old. All copper plumbing, all sweated on. I've developed a leak behind the shower enclosure. Two weeks ago I took the valve assembly apart, messed with it, put it back together leak stopped. Now it's back.

I can't see water coming from the area near the valve but I can hear a small stream of water running behind the enclosure. Leaks out under the floor, about 2 gallons a day. Can a leak caused by a bad valve leak from somewhere besides the valve? Is this a valve problem, something I can repair without ripping out the enclosure, or something worse?

Is the area acessible from the other side of the wall? That's where you may have to whack a hole to work if there isn't already an access panel.

Bad news/good news. Replaced the ball, springs, O-rings, etc. Still heard a slight spraying noise behind the wall. Pushed in on the valve slightly (flexed the copper) and the spraying sound went away. Maybe a problem with a solder joint?

I can access the shower wall from behind. Wife won't be tickled cause it's the living room closet, but better than tearing out the enclosure. Think I should go ahead and take a look?

That's what I would do. I was hoping maybe you would say it was inside a closet or somewhere else unobtrusive.
When you're done just frame the opening with some moulding pieces and a piece of 1/4" plywood and paint it all to match the wall.

Hello, When you remove the chrome plate that is over the valve you will have a hole about 6". Get a little round mechanics mirror and a flash light and see if you can spot the leak then go from there. When you repaired the valve did you maybe put too much torque on the retainer on the front of the valve that covers the seats and springs? I broke a couple of pipes before I learned to heat the nut a little, works wonders.
Good Luck Woodbutcher