Okay, I have an old RCA XL-100 TV (approximately 20 years older, if not older, ultrasonic remote died a few years ago), which has had a problem the past couple of days. I’ll turn it on, it’ll stay on for about a minute or two, turn itself off, and then about 15 minutes later turn itself back on. This will continue for an hour or so, until it finally decides to stay on. When it shuts itself off, I hear what sounds like a motor running inside the TV and the radio near the TV (which has been there for close to a year now, so that’s not the cause of the problem) can’t pick up AM stations because of interference, which is normal when the TV is on. So what’s causing this? And how easy a repair is this for one to undertake? I’m familiar with electronics to a degree, and if it’s swapping out something simple (say the switch) with a readily available replacement (say something that Radio Shack carries) I can do it. I can’t really afford to replace the thing right now, so I’d kind of like to keep it going. (Oh, and there’s no TV repair shops in this town, so I can’t take it to one.)
The first place I’d look is the circuitry that handles the remote control signals. Trace the wires from the sensing transducer (which will likely be mounted on the front panel) back to the circuit board, and look at the components in that general area. Look for things like burnt traces, bulging electrolytic caps, darkened board material around components (indicading long-term overheating), darkened or burnt resistors, etc. Without a service manual and/or basic test equipment, it’s nearly impossible to be more specific.
The best site for info on repairing electronics is Sam Goldwasser’s sci.electronics.repair FAQ. However, TVs are dangerous even unplugged. Unless you already know precisely what parts of the interior of a TV are Really Nasty, don’t open it up. Read all the warnings on Sam’s site about this.
To get a better idea of what might be wrong, you should look for the particular chassis number on Google (web and groups). The “XL” designation is too generic to be much help. There is a really good chance that your problem has occured to someone else and a fix and been found.
But if you take off the back and touch the wrong thing, you could die. Is it worth it?
The motor sound is likely the motor that spins the tuner. I’m going to guess a either cold solder joint, or a bad theromister for the startup problem. Not a difficult thing to fix, but not so easy to find. Look around the flyback for cold solder joints.
FTR, IMHO it doesn’t sound like you should do much with this one, you’re likely not going to find what you need at Radio Shack. MCM, Parts Express or someplace like that has TV repair stuff. Head on over to Hendersonville, Action TV Service is at 175 old Shackle Island Road. In Lebanon, Gabes Electronics is there. If it works, here are link to TV shops near you
Dan