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trouble with blue tube on BD 808

post #1 of 15
Thread Starter 
I've had this BD 808 for six mostly trouble-free years now. Suddenly last night I noticed that dark scenes in movies were looking strange in content from my STB and from my HD DVD player.

Scenes that should be mostly black had a blue-gray foggy look to them. Also on very dark scenes you can make out faint white re-trace lines. Looking through the lens at the face of the tubes, green and red look normal, but the blue tube is signinficantly "lit up" even without any signal, and you can clearly see re-trace lines on the blue tube face.

Does this sound like a tube failure, or something wrong with the electronics driving it? Any suggestions how to diagnose and fix the problem?

The only thing I can think of is to check the g2 setting, but it's been fine for a long time and suddenly this started without anything being changed.

Thanks in advance for any suggestion you have,

Rick
post #2 of 15
Sounds like a shorted tube . You can try swapping neckboards and RGB amps to see if the trouble follows the swap but I had the same issue with my BD 808 and it was the tube .

Tom
post #3 of 15
Quote:
Originally Posted by Rick Wilder View Post


Scenes that should be mostly black had a blue-gray foggy look to them.
Rick

It wants to be a digital.

Adjust your G2s, and swap CRT sockets/video boards between tubes. It could be a bad CRT video output board.
post #4 of 15
Thread Starter 
Thanks guys, I'll try that tonight.

Rick
post #5 of 15
Quote:
Originally Posted by Curt Palme View Post

It wants to be a digital.




Odds are that it's a shorted tube from contaminated particles. Sometimes if you give the neck a good rap (usually when it's out of the projector), you can dislodge the particle causing the short.

When I had my Sencore CR-7000 tube checker, I could burn out the particle(s) causing the short in 4 out of 10 cases.
post #6 of 15
Thats how I fixed it ...
post #7 of 15
Thread Starter 
Cool, so when i open it up tonight to check the g2s i'll also wack the neck of the blue tube as hard as i dare. lol. thanks,

Rick
post #8 of 15
Fixed it useing the Sencore not a hammer ...
post #9 of 15
Thread Starter 
Well, no luck tonight.

I found that the g2 adjustment effects the blue signal as it should, but the background intensity of the blue tube and the re-trace lines are uneffected even if I use the g2 adjustment to turn the blue signal off.

I'm embarrassed to say I didn't get the neck boards swapped. I got the neck boards unplugged from the blue and green tubes, but had trouble getting all the cables and connectors free to do the swap. Maybe I'll have another go at it tomorrow.

One thing I remembered when I went to adjust the g2s - the red and green adjust fine using the indicator lights, but the blue does not. The indicator light has never worked with the blue g2 adjustment, so I have always had to do it just by looking at the color balance of the image. Could that indicate trouble in the board that drives the blue tube. It must be easier to swap a board than a tube.

Also I see that the blue tube has a sticker on it that says it was replaced in 1997. I guess it is newer than the other two. It would be a shame if it has gone bad again.

I'll try again tomorrow to swap the neck boards between blue and green. That should be trivial, I guess, but any tips will be appreciated. Also, what else should be swapped? Are the amplifiers to be swapped the boards with the g2 indicator lights?

Rick
post #10 of 15
Quote:
Originally Posted by Rick Wilder View Post

I'll try again tomorrow to swap the neck boards between blue and green. That should be trivial, I guess, but any tips will be appreciated. Also, what else should be swapped? Are the amplifiers to be swapped the boards with the g2 indicator lights?

Rick

Swap rgb output amps first, neck cards don't have almost nothing that can be broke in this projector. Just few resistors and ceramic caps...

Yes, RGB output amps are those part that have G2 leds.
post #11 of 15
Thread Starter 
Thanks, Ile.

I swapped the RGB amps between the green and blue tubes. The problem remained with the blue tube, so it looks like I probably need a new CRT.

The problem with the g2 adjustment procedure moved along with the RGB amp from the blue tube to the red, so I guess there is something wrong with that amp as well.

The prospect of replacing the blue CRT seems a bit daunting since I've never had one out before. How tricky is that? I guess there is cooling fluid to deal with as well as the mechanical and electrical connections, and then alignment of the yoke and astig magnets?
post #12 of 15
Quote:
Originally Posted by Rick Wilder View Post

Thanks, Ile.

I swapped the RGB amps between the green and blue tubes. The problem remained with the blue tube, so it looks like I probably need a new CRT.

The problem with the g2 adjustment procedure moved along with the RGB amp from the blue tube to the red, so I guess there is something wrong with that amp as well.

The prospect of replacing the blue CRT seems a bit daunting since I've never had one out before. How tricky is that? I guess there is cooling fluid to deal with as well as the mechanical and electrical connections, and then alignment of the yoke and astig magnets?

You don't get involved with the glycol when you change a tube, the new tube has the glycol in it already.

As for changing the tube itself, it all mechanical work removing screws. Once the tube is changed, the hardest part is probably adjusting the magnetics properly.
post #13 of 15
If you can find someone local with a Sencore CR7000 it might clear the short . You might also find one used . If the tubes in good shape try to save it .
post #14 of 15
Quote:
Originally Posted by Rick Wilder View Post

The problem with the g2 adjustment procedure moved along with the RGB amp from the blue tube to the red, so I guess there is something wrong with that amp as well.

Probably led adjustment pot (in rgb amp) have just drifted little bit, that happen sometimes and then it's impossible to get led off.

You can use it without problems, like you described earlier.
post #15 of 15
Thread Starter 
An interesting thing happened today. I was planning to look for a repair shop tomorrow that may have a CRT rejuvenator. Meanwhile I decided to watch the playoff games. They dont have dark scenes and looked decent even with the short in my blue tube.

During the course of the afternoon a lot of the extraneous light coming from the blue tube faded out! Looking into the lens, I still see re-trace lines on the blue tube, but more faint than before. Also dark scenes don't have nearly as much "blue fog" in the background.

It looks like whatever is causing the short may be burning itself up and letting things get back to normal. My fingers are crossed, anyhow.

Rick
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