Hi my name is Eric,
I can help you with your issue,
The part number is XXXXX Tactical switch.
You simply remove the back slide the chassis out , press on the lock tab that stops it from sliding back, loosen or disconnect any wires that are to short.
Speaker wire, grounds, leave the red wire connected.
Turn the chassis over and locate the switch on the front edge of the circuit board.
Desolder using solder wick the pins from the bottom of the switch, pull the old switch off.Install the new switch through the board and solder it on.
Slide the chassis back in, connect all wires, etc.
Test the TV .
screw back on.
If you need more assistance,please tell me your technical ability,
1 I can solder and check voltages and want to know what board/part is bad so I can fix it myself
2 I am pretty good at figuring things out, but do not want to open the Tv up
3 I just know how to turn on my TV
This way, I can help you without getting to technical unless needed.
If I have helped you with your issue please click accept.
If you have more questions you can still respond until this post expires,
I will reply asap