RCA and coax inputs on my TV are both problematic. How can I repair them?

Question

My 22" Panasonic CRT TV is giving me two separate input issues, which developed at different times.

The first is with the coax input. When I connect a device via coax the picture comes through perfectly, but the sound is mostly masked by a loud buzzing sound. The level of the sound goes with the volume setting, so if I turn the volume to 0, there is no buzzing coming out, but no real sound either. Also, it seems to depend on the colours or brightness of the picture. Dark or faded colours seem to produce little to no buzz, but any sort of bright colours will cause the sound to be almost imperceptible amid the noise.

The second problem is with the RCA input. My TV has 2 sets of RCA input plugs, one on the front and one on the back. The back one works perfectly, but there seems to be a loose connection with the front one. Often the signal won't get through, so I have to jiggle it a little and it will work. But then sometimes if it's bumped or even if someone walks in front of it, it will lose the connection again. Recently it has also started giving a bit of a darker picture sometimes, as if the connection is getting through but it's weak.

Does anyone have any advice on how I could repair either or both of these problems? Thanks in advance!

Answer 1

Two different problems both likely to require profession repair.

The sound problem caused by a bad transistor(s) in the audio circuit. Without the schematics it is nearly impossible to detect which one is causing the problem.

The RCA connection has probably come loose from the printed circuit board, and needs soldered.  The only way to to this is to take out the circuit board and on the under side solder the connection back in place.

It is probably not worth the repair cost. as this is a older TV and you are going to have to upgrade to digital in the near future.  

Suggestion. use an old VCR to convert from coax to Video/Audio and hook that up to the rear A/V input. And hook up any external device you need to the A/V in of the VCR.  You can also look for a similar model TV set at garage sale of flea market. Right now they are very cheap.