Fix Annoying Buzzing Sound in Panasonic Viera Plasma TV

I love this 11-year-old TV but it started making an incredibly annoying buzzing sound that increased as the screen got brighter. The culprit are loose screws that hold the inner circuit boards in place. This is a common problem with this era of Panasonic TV and Panasonic makes a replacement screw kit (#XYN-3FF66FJ) with lock washers for a permanent fix. However, it has since been continued and 3rd party kits are expensive. Here's a temporary fix that should get you some more years of enjoyment.

Philips head screwdriver

This should be self-explanatory, but safety first! Unplug the power cord from the back of the TV. (You'll need to anyway to get the back off)

Go around the outer edge and remove all the screws (there's 14 or so of them). Be sure to keep all the screws you take out separated in containers so you'll know what goes where later on. You'll see arrows pointing to them labeled "ST4." On the very bottom there are 2 more slightly different screws with washers attached that are easy to miss.

There are a few teeny tiny screws holding the back plate to the inner circuit boards, on the left and right sides. Be careful not to drop these, they're easy to lose. There are 2 more on each HDMI port.

Remove the 2 screws by the component inputs and keep separate from the others.

These are all different size screws - 4x large bolts with washers that go into the stand and 3x "M4" screws in the middle. 2 more small screws hold the bracket in place.

Remove the 4 plastic clips in the back center. These are the final things holding the back plate in place.

Now you're ready for the big step - removing the back panel! You'll see there are 2 small hangers in each corner that you must lift it up and over. BE CAREFUL of the sharp metal edges on the inside of the panel, gloves would be recommended. Also be careful sliding it off the input and control panels.

Now at this step, it helps to plug in an exterior HDMI device (Xbox 360 worked perfect to provide an immediate bright backdrop) and plug the power back in and turn the TV on. This will help you isolate where the buzzing is coming from. It was immediately evident in mine as the top left corner screw was almost all the way out and actually shorting out, creating an electrical spark and leaving burn marks on the board. Good thing I caught it, that's a fire hazard! I believe the foam padding under the board in the last photo was added by a repairman who fixed this same problem way back when I got the TV.

DO NOT tighten or touch any part of the TV until you unplug it from power, as you could be susceptible to shock. Once it is disconnected, go through and systematically tighten each screw holding the boards in place VERY CAREFULLY - I'm talking like 1/100th of a turn of the screwdriver. Just a little bump is all most of them need.

Plug the power back in and check for more buzzing, unplug and tighten as needed.

Once you're fairly certain you've eliminated the problem (I couldn't 100% get rid of it, as there seemed to be a general electric hum from the components but it was still a VAST improvement), carefully put the back panel back on - go along the edge & make sure it's seated right and that the hangers pop back into their holes. Then start methodically putting those screws back in!