CurtPalme.com Home Theater Forum

[comm]

I finally got the new LUG installed in my Marquee 9500. I moded the neck board for the LUG (Tied a 1M Ohm resister from pin 7 to ground and drilled out 6 for the G2). I just powered it up for the first time and I think the damn thing burned a small line on the phosphor. Once it powered up it seemed to work fine. Any idea what happened????

[draganm]

I don't see a line burned into the Phosphor? I see a normal wear pattern from previous usage and some peices of debris which isn't uncommon in Lc chambers. Can you take a better pic maybe?

[PaulB]

These 'floaters' usually cast a shadow, look closely into the face and see if thats what it is, a torch can help. Hopefully thats all it is.

I had a couple from when I removed the Bellows on one of my tubes. It will float up to the top and outta the way eventually but if you can't wait or like me just want nice clean LC Chambers you can do what I did, open up the marquee again, open up the bleed/filler hole, get a syringe with a piece of heatshrink on the end of it and suck that sucker out!

Was the tube sold to you as a brand new tube? It does look like you have some wear there. A brand new tube should have no wear.

[comm]

Yes, the tube is not new, it has some wear. I changed the levels in photoshop and circled the area in which I am concerned. I am pretty sure I did not see that before I turned the unit on and the image was defiantly dimmed there. Of course something in the way would cause a shadow. Hopefully I am just being paranoid, but it sure looks like its on the phosphor and not in-front of it.

[PaulB]

Difficult to tell what it is. I don't think spot burn looks like that though. Could be marks on the tube face from when the tube was removed from whatever pj it was in before of maybe just some hairs or something. Again, I'd suggest trying to simply suck it out and see if that works. If that doesn't work well, maybe it needs a closer inspection.....!

[JustGreg]

The not knowing for sure would drive me nuts. I'd have to drain it, break it down, flush and rinse, and do a good tube face to eyeball inspection.

Now for my related ig-nant question....is it possible for something like a piece of a heater, or whatever, to have broken loose and floated around inside while the tube was transported face down, and it left that mark al la EtchaSketch?

[comm]

It is driving me nuts for sure. I used a flash light and it does not seem to cast a shadow like the rest of the floating stuff does. I would just take it apart but the silicon on a Marquee is a PITA. I guess I could take the c element out?

I guess maybe I should ask this question, because I really don't want to power it back up without knowing. Is burn even possible as it is pictured? I know it wasn't there when I filled the chamber and am 99% sure it wasn't there when I installed the tube. The edge of the two lines touches where the edge of the raster was. Would it be possible for it to burn the tube on the edge like that and then power on OK?

Thanks for the help everyone.

David

[JustGreg]

I personally wouldn't know but I want to know, so I'm posting more right now as a way to keep this thread near the top while waiting for an answer than I am offering an answer. From what LITTLE experience I have in relation to repair of a pj, I'm going to guess the answer is no; it isn't a spot burn. I suppose it could be a random bit of cathode or such that as soon as HV was supplied did a little lightning bolt dance and left that mark. It really does look like doodling or something random (chaos theory anyone?) If you followed the LUG conversion correctly I don't see that as a consideration however, 'things' happen. (more chaos theory)

I suppose you could remove the fill plug and poke a thin piece of insulated wire down there and see if it moves. If it does that's great. You can pour out the glycol and filter it through a coffee filter and reuse it after cleaning the chamber. If it doesn't move then something has marred the phosphor. Sooner or later you're going to have to turn the thing on and throw up an all white and all black field to see if it's visible. If it isn't, I personally would 'drive it 'til it drops'.

[Saeid01]

I would post a white screen and if those scratches come up as yellow, then they are burns from arcing could have been caused be loose video feed to the neck card. that happened to me on the blue tube, if yours is not the blue tube then it may show as a different color.
If it does not show on a white screen then it is not a burn and just some scratches on the exterior of the tube face
Saeid

[comm]

I tried some wire to see if I could move anything around and had no luck. I am hesitant to turn it back on as I don't want to make it any worse. The mark was definitely there while the tube was on, it did not happen on power off. Is there something I should check before powering back on? I was noticing the mark almost looks like two small sine waves didn't know if that was significant or not.

Here is a picture of the neck card mod, I don't think I messed that up:

[voodoo7869]

the mod looks fine that is not your problem I would definately check if it is a floater it might be stuck on the glass use something plastic or insulated bell wire just stir it up it does not look like spot burn

[comm]

Thanks for the help everyone.

I got some much better pictures today. I tried to move/scrap it off the tube face with large paper clip but had no luck. I noticed that the paper clip cast a shadow onto the phosphor when touching the tube face glass where the lines do not. I tried to show this in the first picture. As much as I still want to be wrong, I am pretty sure that the mark is in the phosphor.

[Nashou66]

That definitely is on the face of the tubes phosphor, looks like some stray electron beam went hay wire in there, like one of the deflection circuits failed to control the beam and the scan fail failed as well. Any one else? could that be what happened?

Athanasios

[km987654]

From direct personal experience that is not spot burn!!

[ecrabb]

Maybe not typical spot burn, but it sure looks like V and H deflection might have gone whacko at one point. I didn't see it the first couple of times I glanced at it, but it sure looks like four similar events. Based on the description and the photos, it looks like a beam burnt the phosphor. As for how it happened, that's another mystery.

Here's another theory. Is it possible a piece of debris came loose inside the tube during shipping, fell on the phosphor on the table while you were installing the magnetics, and scratched the phosphor when it fell off. I know. Not likely, Just trying to come up with an alternative. I'm still guess it was some sort of deflection problem that's way beyond my ability to diagnose or understand.

SC

[perisoft]

When I saw that picture, this is what I thought:



May god have mercy on my soul.

[MikeEby]

[km987654]

I have seen phosphor fall away from a tube also but usually it doesn't look like some has draw on it with a pencil. Does this mark show up on the projected image?

[ecrabb]

I agree. That's why I still think it was some sort of weird deflection failure.

Perisoft... Dude, that was weird... even for you.

SC

[perisoft]