|
You would need a schematic to even BEGIN to troubleshoot this issue.
The issue sounds like it is either in the input switching circuitry, or the interface between it and the main microcontroller. You would need to look at the signals from the microcontroller which select the various input sources and see if they are actually toggling high and low as required.
Once you figure out where the problem is, you will then need to replace the failed component. It could be a simple failed diode or transistor holding a control line high or low, or it may very well be part of a custom ASIC in a huge pin count PLCC package, that will require really good soldering skills to replace (if RCA will even sell you one). And if you are dealing with something like a BGA package, you are pretty much screwed as far as replacing it without specialized, expensive rework equipment.
Issues like these are why component level repair of this stuff is rarely done, and entire modules are swapped or the whole unit is tossed and replaced with a newer model.
|