Bezel screws & popping - my experience so far:
A couple of inmates here suggested loosening the bezel screws to where they are just snug. My S64's popping was progressing a bit but not nearly to where I would return it. But I was obsessing about it so I figured I'd check the screws.
Among other things, I was a mechanic for several years and obtained my ASE master certs. In that light, here are my observations:
The tightness of the screws varied wildly and at random. No rhyme or reason as to the locations:
1 screw was 3 turns out from tight.
2 screws were loose - not seated.
3 screws were way excessively tight to where I wondered if the head would strip or the screw might twist off. This causes me to believe they were installed with impact or "rattle-wrench" type drivers. 1 of those 3 was insanely over-tight. As in, wrap a rag around the screwdriver handle for traction... and "CRACK!" when the screw broke loose but thankfully didn't twist off. These small screws must be made of some kind of unobtainium steel 'cause that one felt an awful lot like 60 inch pounds!
I'm amazed it didn't strip during assembly. Looks to me like Panny could use to do a seminar for their assembly techs on how to properly set a torque limiter; assuming their drivers even have them.
Some screws seemed to me to be "merely very tight" for very small screws like these. Some were right at contact plus "snug".
As previously suggested, I put them all at contact (bezel seated if it had bowed up when loose) plus "snug" or maybe just a 'guestimated' added 2 inch pounds.
I noted in the area where I think the popping was coming from, there was 1 over-tight screw and a loose one. I don't really think that means very much.
When the tight screws would crack loose, the back panel sheet metal would resonate. This sound was identical to the tone and timbre of most of the popping. I heard 2 mild pops this a.m. when the TV was cooling after shutdown. So with power off, I agree with what El Matadurr said: What my TV is doing is not the power board.
I had to hold quite a bit of opposing force on the bezel to prevent stripping the screw heads on the 3 super tight ones. I could have used my Ryobi impact driver to get them loose without doing that, but chose not to. So now I have fingerprints all over the bezel.
No big deal; easily cleaned up with I'm figuring a fine/clean micro-fiber cloth and distilled water.
I'll report back on popping in a week or so. Regardless, I won't be going back to over-tight on any of the screws.
If anyone else does this, do it at your own risk because of the above wild variations. You might damage a screw head or twist one off. Likewise, opposing force if not done right could lead to cracked glass, IMHO. If you do this, please choose your screwdriver carefully. Neither #1 nor #2 Phillips fit properly - the screws are in between. With my screwdrivers, I decided #1 had more engagement though it was still a bit loose. I couldn't find my hollow ground screwdriver tips for firearms but suspect a #1 Phillips in one of those would be better or maybe correct.
For now, I've gotta clean up that bezel - looks like I just had a troupe of 'curtain-climbers' in the house!