UPDATE: Weird RCA TV Problem

Hi, It looks like the problem is fixed (see below for details).

This is the first time I have encountered a button switch/s that tested good (no "leakage" at 50V test), but turned out to have intermittent "leakage".

Thanks to everyone who offered their help, Brad

Hi, > > I finally found something that may be the cause of this problem. I will >report back in a week or so after I confirm it. > > This was the first test I performed on this TV, which "past the test". >I used a capacitor tester's "leak" test (very sensitive) set at 50V and >checked all the button switches. Absolutely no sign of "leakage". >I won't tell you all the other things I did. Sometimes it pays to re-test. > > This time, when the TV started it's off/on "ritual" again, I unplugged the >TV and I performed another "leak" test on the button switches. >Wow!!! now I have a "leak" indication. Imagine, an intermittent "leak"!!! >I opened the circuit trace to all the button switches. Now, I will use the >remote control on this TV for the next week or so to confirm. Please >"stay tuned". > Brad > >> >>Hi, >> >> Has anyone fixed a late model TV (mfg 2005/2006) with this problem: >> >>You turn on the TV, after the screen lights up, etc. the TV turns itself off. >>About 5 seconds later, the TV turns itself on, etc. You have to pull the >>plug to stop the off/on cycle. Sometimes, you turn on the TV and it will >>play for a while before this off/on cycle begins. >> >>IMPORTANT: The TV may work just fine for a few days, then it happens. >>Eventually, the TV begins to work fine again for another two or three days >>before it happens again. >> >>I have serviced TVs for years and I performed many tests on this >>RCA TV, chassis M134C (mfg 01/06). >> >>I thought about replacing the micro or the eeprom, but I could be >>wasting my time and money? >> >> Thanks in advance, Brad >> >> Before you type your password, credit card number, etc., >> be sure there is no active keystroke logger (spyware) in your PC.

Hey Brad,

I have encountered a similar problem a couple times with widely different devices in the past twenty years, and it turned out to be a power supply problem in both cases. In the first, someone had replaced the correct fuse with an incorrect type, and the replacement "blew" but continued to operate due to arcing across the resultant gap. When the fusing element heated up it curled, opening up the gap left by being "blown." When the gap widened, it stopped arcing and consequently began to cool. As it cooled, it uncurled, closing the gap again... Up and down, at regular intervals. From a blown fuse of the improper type. Too crazy to be believed, but I saw it and fixed it. Saved the fuse just to remind me of how crazy some problems and fixes can be. This was with a 1/4 million $, high-speed printer in a mainframe computer environment. Too much.

The second time was with a "boombox" type radio, but only when it was on the power cord and not the batteries. Turned out the cord was not the original, and didn't fit well. Loose connection heated up, the round "contacts" in the cord expanded, and the radio shut down. Five minutes later they had cooled and contracted enough for it to come back on. New cord fixed it.

Shaking my head just thinking about these two. If your problem comes back, try not to make assumptions about what is/is not causing it. Granted, it sounds like you found the problem, I just thought I would share my own experience, as your leaky switch sounds like another electrothermal anomaly.

Best regards,

Dave