Puzzling IR remote control problem

NeverExpectPowerAlways · 2007-03-03T03:38:22+00:00

I hope I've come to the right place to get some helpful hints.I am working on a Mitsubishi TV, model CS-2056R, made in 1988, specifically, the IR remote receiver circuitry.The remote function for this unit began failing some time ago. At times, it would just up and quit working and then just as suddenly, it would start working again. At first, there did not seem to be a pattern, but after some months, one appeared. The remote would never turn the machine on or control it for the first 10 minutes or so, sometimes for much longer but mostly only for the first ten minutes. After this "warmup" period the remote control function would kick in, but it would die and come back to life without hint or warning.I finally decided to see if I could fix it. Without going into detail, I am 100% sure that the handheld unit is not the problem. After searching the web and the newsgroups and spending several hours tracing the traces on the tuner board of the TV and taking readings with a multimeter, I decided to try changing some of the larger electrolytic caps used to filter the AC and anything over 100 microfarads or 50 volts (BTW, I don't do this stuff for a living, just a part-time hobby). I also changed a resistor that looked like it had failed.I also took apart the IR receiver module and changed the three tiny electrolytic caps within. About this time the remote function ceased entirely. No matter how long I let the unit warm up, the remote would not function.Today, after more web and newsgroup searching, I decided to buy a four dollar Radio Shack IR receiver module and guess what, it worked! I mounted the Radio Shack module on the tiny stock IR receiver circuit board and soldered the three pins to the appropriate spots, held my breath and hit the "power on" button on the remote and the TV turned on. I watched an old episode of Perry Mason and then turned it off.Now, some four or five hours later, the TV will not respond to the remote. The Vcc voltage to the IR receiver module...

Mar 03, 2007 21 Replies

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NeverExpectPowerAlways ha escrito:

firstly, well done on fixing that set. Just ignore the idiots who put you down instead of offering useful advice, we all have to start somewhere and your posts showed that at least you had a clue about what you were doing , unlike some gung-ho, have-a-go fools who often post on here, who are IMHO more deserving of put-downs, if only for their own safety!

Even though analogue is set to be switched off, remember that you will still be able to use standard TVS by plugging in a set top digital decoder box Of course, corporations and salespeople will not exactly rave about that, as they want to you dump good stuff in the landfill so they can sell you what *they* want and not what *you* need!

regards,

-B.

Thanks, B

I will probably never attain the level of knowledge and experience of most who post here, but I have a basic understanding of electronics and have managed to resurrect several pieces of high quality vintage stereo gear from the 70's, and a 96 Kia Sephia that suffered a short circuit that fried the computer and melted the insulation on several wires in different bundles that subsequently shorted to each other. It took a while but I did it. It's amazing what you can do with a VOM, a bit of knowledge and a lot of perseverance.

This was my first foray into a TV set, however... at least to fix it. As a kid, I was given an old broken TV and a set of schematics for a 50 watt CW transmitter. Except for the 6146 tube and socket and an aluminum box, all the parts came from the TV set. That was when I learned just how dangerous the inside of a TV set could be. Now that I think back on it, the guy who set me up should have warned me about the high voltage stored in some capacitors, even with the set unplugged. Maybe he did. I can't remember. But I remember the shock I got when I touched the wrong things.

Thanks again for the kind note.

Jack

Puzzling IR remote control problem

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