CRT RPTV Went Dark Last Night!

Discussion in 'Displays' started by Dave Ringkor, Oct 27, 2005.

  1. Dave Ringkor

    Dave Ringkor Stunt Coordinator

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    I have a Panasonic 47" CRT rear projection HD-ready TV that's about five years old. It's worked great this whole time (aside from when I scratched the screen, doh). Last night I was out of the room and when I came back in, the picture was very dark and the colors were tinted weird, almost as though one of the component cables had come loose. But the problem is evident on all inputs and even when using the built-in CATV tuner. I adjusted the TV so it's almost watchable by turning the "picture" control all the way up and the "brightness" most of the way up, but those settings had previously been calibrated (via Video Essentials) at much lower levels. I figured maybe I lost one of the lamps -- blue and red are strong, green not so strong -- but all three colors are visible. Any idea what might be causing this problem? I do have the service manual somewhere, which I bought to do the manual convergence years ago. I wonder if it has any pointers.

    Ironically enough, when this problem happened on my living room TV, I was busy setting up a new home theater area in the basement with a bunch of older components I hadn't used in some time.

    Other oddities are that recently there has been a spider hanging out inside the living room TV, though I don't see how that could have caused the problem. Also last night my smoke detector went off, I thought because there were candles burning in the house. But now, who knows?!
     
  2. Bob Maged

    Bob Maged Stunt Coordinator

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    My guess is that the spider worked its way down to the crt guns and caused an arc which fried the spider along with some circuitry (or the green gun itself), and the little puff of spider smoke set off the detector.
     
  3. Tim Jin

    Tim Jin Supporting Actor

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    Is the picture dark on all inputs such as 480i, 480p, 1080i, or is it only happening on just one, such as watching standard def channels?

    My old dead Panny 47' (pt47wx42???) did the same thing. The tech could not locate the problem. I ended up getting another main board under warranty. Actually, I went through 2 main boards and 3 new guns and countless of repairs before they deemed it to be crap and replace the TV.

    If your tech cannot isolate the problem by replacing the circuritry, you are better off at getting an new tv. The main board are like $600 and at the time, (3 years ago) the tech could not get a fresh new board because Panny had a limited supply.

    Hopefully, the tech can isolate the problem for you.

    It might also be the Evil Pop, but I doubt that because your guns are well settle in by now.

    Keep us posted.

    I really wish you the best because when I went through the similar problem, I had to wait for over a month to get the board back from Panny and than everything else went south.

    Thank goodness for the replacement. My old Panny was junk from the get go. 30 days after out of the box, I had my guns replaced. It was 16 months of hell.

    I made a new friend with the service guy.
     
  4. Dave Ringkor

    Dave Ringkor Stunt Coordinator

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    Tim, you had the same model I have. Until now mine has been functioning well though. To answer your question, the picture is dark on all inputs. I went home for lunch today and played around to try to come up with more data.

    As I said before, the picture was very dark and lacked a lot of greens, so I thought the green gun might be bad. I changed the aspect ratio to 4:3 to see if the bars on the sides in that mode are gray like they're supposed to be, and voila, they're now blue!

    So I dug out my service manual and entered serviceman mode and did the purity test, which displays a white screen, followed by blue, green, and red screens (not sure of the order). All the screens, including green, looked good! So I'm thinking the green gun itself is fine, as are the other two. I wonder if it's possible that some service-mode setting got reset last night. I think the service manual lists the defaults for all the settings, so tonight I plan to go through and check them out.

    I hope I can fix this at minimal cost, because I hadn't planned on keeping the TV long anyway -- I'm going to build a home theater room in the basement with a front projection TV and move all the current audio and video gear down there, and purchase a smaller LCD or DLP for the living room and use it for "normal" TV watching. But I'm not ready to buy the projector for downstairs yet, and I don't want to replace my current home theater TV with a smaller one and not be able to watch movies on a big screen. Argh.
     
  5. Dave Ringkor

    Dave Ringkor Stunt Coordinator

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    It popped! Tim, thanks for mentioning that. How about that, and after five years. I found an article about the evil pop on on www.panny.tv and tried the remedy -- taking off the front panel and adjusting the rgb pots. I turned up the green, did the user-level convergence, and now everything looks good. My brightness and contrast are still set higher than they were before, but the picture looks right on all inputs.

    Now I need to recalibrate the TV with Video Essentials, but I've loaned the DVD to my coworker and need to get it back...

    Where would we be with Home Theater Forum and Google?!
     
  6. Tim Jin

    Tim Jin Supporting Actor

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    Dave,

    I'm glad that I could kinda help you. Sorry for not replying to you sooner. I forgot to check the email notification.

    Wow, after 5 years, it finally popped!

    I'm glad that you are getting it resolved.

    I never really understood why the old Pannys had that problem. I think my previous Panny popped like 3 times.

    It's still a great TV.
     
  7. BobbyMac

    BobbyMac Auditioning

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    I wish mine would break, so I could finally convince the wife that it's time to get the Sony SXRD.
     
  8. Dave Ringkor

    Dave Ringkor Stunt Coordinator

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    Oh, so get this. Last night, after I'd fixed the TV, my girlfriend said she would actually like to have gotten a bigger one (TV). Dammit. Oh well, it's really not in the budget anyway...
     
  9. Tim Jin

    Tim Jin Supporting Actor

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    That's good news. You can **start** shopping now...

    Are you able to calibrate the gray scale?

    I know that my gray scale were way off the scale after the guns popped.
     
  10. Dave Ringkor

    Dave Ringkor Stunt Coordinator

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    Yeah, I'm gonna do the grayscale tweak but I need to get my Video Essentials DVD back first so I have the test pattern. I think I'm going to redo the 64-point convergence too, as long as I have the service manual out.
     

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