Question about Panasonic PT-47WX51 47" Rear Projection Television
Hope someboby out there can help. TV now 4 yrs old and is a great set. Recently it has been changing skin tones especially to a horrid lime green. The effect only lasts for 5-20 seconds, some days not at all and others a few episodes over a few minutes. The picture / convergence are all fine. I want to knock this on the head before it becomes a real problem. Regards, Ron Huston
You say changing skin tones and green problem. Well it sounds like CRT maybe going. Have this set been used for gaming? (Playstation, XBOX, etc) If so this has alot to do with it. Also you can see problems like this if loose connection around crt boards(on neck of tubes) check all three good. sometimes you can tapp on slightly and see a change. Use something rubber and be careful not to damage yourself or anything else.
Posted on Sep 04, 2007
Usually what I find in a case like that is that there is a loose solder joint on the CRT board of the red picture tube. When the connection is good the picture looks fine but when it lets go the picture turns that awful greenish-blue. On most sets the bottom front of the TV will disassemble to allow access to the CRT boards, and the solder joints can be resoldered quite easily. If you do not have experience resoldering boards in a projection TV then allow a qualified tech to handle it for you.
Posted on Aug 07, 2007
On most sets the front just pulls off, being held in place by little rubber or velcro fasteners. Pulling on the sides gently is all that should be required. Then there might be a panel that comes off by removing some screws, revealing the bottoms of the 3 picture tubes with their CRT boards. Obvoiusly, make sure the TV is unplugged when doing this!
From that picture, red is usually Gun 1, the tube on the left. Green is always center and in Sony sets, the blue is always the right one. Turn the set on and look at the top of the picture tubes and it will be very obvious which one is red.
Yes, we are talkimg about the board at the base, with the shield soldered on. You must remove the shield to resolder the connections under it. When resoldering, the most likely places for a failed joint are the transistor on the heat sink, the tube socket itself and the jacks where the wires connect to the board. The board is small so it is easiest to just go ahead and resolder them all. Use a small soldering pencil and some good 63/37 rosin core solder. Although it is not absolutely necessary to put the shield back (99% of sets do not have shields), I would replace it, especially since it is easier to put it back than it is to remove it. Inspect and resolder the solder joints on the other boards as well. Usually there are wires between the boards so a loose connection on a jack on the green board can cause the red board be intermitten.
I do hope that by "no green for a couple of weeks" you mean no abnormal green, and that the green in the picture is only where there is supposed to be green. In that case, I say "great job!"
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Mike - many thanks, I guess the front just pings off or does it have secert fixings, or does the back have to come off first???
Regards
Ron
Mike - thanks again - am a mechanical engineer with lots of hands on factory experience. Ill pull the front off in the next few days and will send you a picture for further guidance.
Regards
Mike,
Cover off as per photo. Which is the Red Gun?
Each gun has a board up at the neck and one at the base of the gun
Regards Ron
Mike,
I assume we are talking about the board attached to the base of the gun(and not the one attached to the neck) Each has a metal cover over the solder side of the board. I assume this has to be removed, then all solder joints remelted with a small solder iron- does the cover have to go back on?
Regards
Ron
Took the board off, removed/reconnected all plug in connectors. The main connection ie. board to gun was a little wobbly and the pins at the bottom of the gun showed a purple look = heating. From my lighting days that oxide film indicates a connection not running at 100%. Gently cleanded off film with some 600 W&D sandpaper. No green for a couple of weeks !!
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