Here's a weird problem...
 

RCA-branded 20-inch 'TruFlat' CRT TV, Model number 20F512T, chassis number M123SP, built May 2006. (I suspect many TVs used this base design under several brand names.) When plugged in, it sits for several seconds with the standby LED on, unresponsive to the power button. It comes on after a bit, immediately displaying the picture controls menu but otherwise okay...none of the front (top) panel buttons work unless they are pressed repeatedly, and even then the results are hit and miss. Same results using the buttons on the remote. I can't get any of the video and audio inputs to work, either. Hosing and drying the mainboard did nothing. I have never seen this odd issue before, and it has me stumped!

try disconnecting the front panel push button switches-they are known for this type of behavior.

I'lll definitely try that after work tomorrow. I'm assuming I'd just use the remote, then? I am using a universal, and though it does work, it doesn't support all functions. (I might add that the TV, when responding, is showing a component video input onscreen that doesn't exist on the rear of the set!)

On a number of these RCA "tru flat I have seen the cpu go nuts. Sometimes you can freeze it and it will work for a short period of time. It will eventually start turning itself on and off so many times the horizontal output shorts.
They also eat flybacks. I hate to say it, I don't take them in for service anymore.

If its not the control panel look to the Vcc for the micro & Eprom.
The micro seems to kinda want to work & the features stored
on the Eprom. Biggest thing is this is probably a chinese
RCA. We had one that was just over a year old, couldnt get
service info or most parts. Wouldnt even take them in anymore.
If you have seen a real RCA you will see no evolution in this chassis,
its just a cheap chinese set with an RCA badge. In any
case it prob. isnt an easy fix if at all, you may end up putting
it down......
Not to worry there are millions of better sets out there for free.

good luck
73 Zeno

Thanks for the tips, guys. Looks like this one may not be worth my time, but I'll still try the suggestions, just in case.