Panasonic CT-27D21E w/ Chassis KP338 turns OFF & ON w/ clicking vs. heat?
1st – Stats = Panasonic CT-27D21E w/ Chassis KP338, Made Mid 2000, Purchased Christmas 2000, New in Box, No Damage, Same Owner, Never Dropped, Set on TV Stand, Never Moved.
2nd – Worked fine until about 4+ months ago, (heavy use – TV on 16+ hours per day) then, Clicking Sound (sounds like Relay), wherein Picture AND Sound go away together, and then come back together, anywhere from 30 secs to 10 mins later, usually shorter. When started, it would be a solid Click Off, w/ time lapse. then solid Click ON, and could cycle several times, 2-10 times, with various times being On, before Off again. Anytime when this happens, there is NO way to turn the TV off from the Remote. Testing has shown, that when it cycles Off and I perform a single Power Off Command from the Remote, it is not detected by the TV and it will come back on, when it cycles.
( I have never tried the front buttons on the TV) (Has been unplugged for 1+ min to clear all power, no change)
3rd – After over two months of this, I took the back cover off. I pulled the circuit boart out about 4” and never got the problem to occur once over three weeks. After the three weeks, I then blew out with high volume air flow ((not compressed air) large clean shop vac in blower mode with reducing nozzle and done very thoroughly). There was a lot of accumulation from 5+ years of use, in a smokers room (2 smokers).
4th – Reassembled back of TV and problem started a few days later, but not as bad as first, would usually cycle only once, within the first hour of being on.
5th – Post 1 month back cover reinstallation – Usually within 1-2 hours, sometimes sporadic, Clicking without interruption many times, sometimes minor picture glitches, AND of course, complete Off and On cycles with much shorter cycle times now and fewer repeat cycles, BUT I am getting concerned about what seems to now be Relay Chatter Sound at times (less than 10 times of single click, or clicks (2), of chatter, per viewing session).
6th – More sensitive at times to Heat (+75), and seems to be more active anytime when components are cold – once internal cavity heats up and air flow establishes, problem seems to level out, and in fact, usually does not occur at all after TV has been on for 2 hours plus, and can stay on for 10 hours, seldom without further problem.
7th – Was able to download a similar drawing of a Chassis (motherboard) and only saw 1 Relay, but the schematic was missing, so I could not follow the power to confirm Picture and Sound loss together, being from the relay, or, a power supply problem.
TV Picture is Great, at normal consumer settings, no extra adjustments such as more contrast or brightness, etc.
I am thinking a possible cold solder joint, weak coil in relay, failing Cap., or Res., etc. I am capable of replacing components, if, I know what to replace.
Any help anyone.
Thanks.
Sssttu2@hotmail.com
Stu, December 2006
