CurtPalme.com Home Theater Forum

[Francesco]

Hi all, I'm trying to change the tubes on my Marquee 8000. I've seen that the old green tube is less bright than the other two: is it normal? I can easily read the menu text, but the red and blue tubes are much brighter.
Could it be simply the age or there could be some other problem? Consider that tubes have approx. 9000 hours on them.

Last queston: do I have to measure the distance between the tubes and the lens/tube frame so I can set up them the very same way? Or I can set this up from scratch?

Thank you, and sorry for my english...
Francesco

[Sparky015]

Francesco,
What you are seeing is normal. New tubes will always be brighter than a tube with 9000 hours on it. All you can do is adjust the green as best you can to match the new blue and red.

I'm not sure I quite follow the second question. Maybe post a pic of what your referring to? Their are locating pins that put the tube assemblies back in the right spots. All you will have to to is rotate the blue and red to converge on the green.

[Francesco]

Paul, thank you for your reply. I have 3 new tubes: 2 brand new and the blue is regenerated (is the word correct?) with 100 hours on it.
I've read here on curtpalme that "common faults of the CRT socket board is streaking of images, low light output, excessive brightness or no light output from one tube at all " so I am a little afraid that the low light from old green tube could be a socket board failure... that's all.

As per the other question: I've removed the old blue tube and I had to remove the three springs that hold the tube to the lens mount. The tubes are at a certain distance from the lens mount, look the green and red tubes: there is a little gap between them and the lens mount, it's where the spring is located:



Do I have to take a measure of that gap? If I understand your reply correctly there is a sort of guide or something similar to put the tubes into the right place...

[Nashou66]

You removed the tube wrong, the entire top plate with the A.B.C,D bolts comes off. the the tube assembly comes right out with the face plate you left in shown in your picture.

Now getting schiemflug right will be more difficult. Id measure the gap from one of the other tubes at the red cap. this cap is set at the factory, make that same bolt the same distance. Also it is not easy to get those springs back on I looked for a slightly longer bolt with the same threads and tightened up one corner then tried to put the others in with the original screw, then I removed the longer bolt and put the original back in.

Also after re tubing always check your G2 values again in the service menu. You may have to lower the new tubs and raise the older ones.

Athanasios

[Curt Palme]

Check the power supply to make sure the filament voltage isn't too high as well.

[Curt Palme]

Check the power supply to make sure the filament voltage isn't too high as well.

[Francesco]

Thank you Athanasios. At least we did not remove all the tubes... but we removed all the red caps (do you mean the red plastic caps like the one shown in this pic near the blue tube? If so, I did not take note of their position, where do I have to put them? I have two big caps and two small)



By the way, how do I remove the entire tube + plate assembly?

Curt, the previous owner of this projector replaced the power supply so it should be ok, but I'll check it anyway. What do I have to look? Sorry for the dumb questions but it's my firse projector...

[Sparky015]

this may help with some of your questions. This shows you how to tear down a Marquee. The pics show a 9" machine, but the 8" aren't much different.

http://www.curtpalme.com/Marquee_Teardown1.shtm

You may want to PM Tim, as he may know the factory setting for the schiemflug. I still have a red 8" Marquee tube assembly I'm trying to sell. I will see if I can't measure the schiemflug setting on it and send it to you, as it should be pretty close to factory.

Yeah, my comment around the locating pins was assuming you removed the entire tube assembly with the schiemflug plate and springs attached.

[Tim in Phoenix]

[draganm]

it's rare to see someone put new tubes into an 8000 chassis. Upgrading to an 8500 chassis will yield more perfromance gains than those new tubes can.

[Sparky015]

Tim, is that dimension the same for a 9" LC as well?

[Francesco]

Paul, Tim: thank you for your precious help... any suggestion is more than welcome.
Dragan: I took this 8000 for about 130USD (100EUR)... it's my very first projector and I wanted to stay on the cheap side. Maybe in some future... who knows?

[Nashou66]

No Paul, Lc is a whole other bird.

I just kept the LC plate about 1mm from the Swivel plate/housing.

Athansios

[Sparky015]

Good to know. I believe I did the same when I retubed, and made sure the glycol fill was appropriate for that bellows compression.

[Tim in Phoenix]

[Sparky015]

Oh, I suppose your right. I just remember that I could tighten both screws at the same time and get the C-element much closer to the tube face, but I think they have to be tightened enough in to allow the pivot pins to go into place, so I guess your right. I remember I kept that in mind before I did my glycol fill to avoid unecessary pressure.

Anyway, sorry Francesco, didn't mean to hijack, just thought I would ask while on the subject.

[Francesco]

No problem Paul, it's all new and interesting to me

[Francesco]

[JustGreg]

Congratulations on getting a CRT projector Francesco! Too much these days people are opting to go the digital route. That's cool if you just want to plop it down and play games or watch movies; but if you love tinkering then you'll love a CRT projector. I won't get into the age old argument of whether digital is better than CRT. It doesn't matter.

Nobody mentioned it yet so I will. The green tube provides the majority of light output. Just look at the G2 settings you're supposed to set the tubes at (available in your manual or at the site below). You can also find an awesome collection of information at Tim's site in addition to what you need right now. Here's the page for the G2 settings:
http://www.etechvideo.com/techtip1.htm

Green G2 is set to 90 for the green tube. The highest of all three tubes. Of course this number will change a bit later on as you get into grayscale adjustment but talking about that right now isn't part of a tube swap. You will want to make sure the G2 numbers are set to default before changing tubes. Might not be possible now you have the projector partially torn down.

Make REALLY sure you connect the G2 wire to the correct pin on the neck of the tubes after reinstalling the neck boards. (You called it a socket board...which literally is what it is but it's called a Neck Board). Usually the pin you aren't supposed to connect it to has a bit of plastic sleeving on it but make sure you know which one anyway.

Change one tube at a time and power the projector up after each one. Make sure you have every cable and plug reconnected where it goes before turning on the power. It's easy to be off by one pin on some of the connectors so triple check before pressing the power button. You can leave the top retainer plate off the tubes while checking it out after each tube swap. You'll only need that on later when all the tubes are in.

As Curt mentioned, make SURE you check the P14 filament voltage! Too high and it will drastically shorten the life of a tube, or radically reduce the light output from it. And there's no recovering the tube once the filament is toasted. If I were you, I'd check that voltage before I removed the tubes. Better to take a chance with your old tubes than your new ones right?

And you removed the bolts and springs....ouch. You're going to pull out some hair dialing that back in but like Tim said, start with 3/4" (17mm). I made a gauge to reset my to factory default. You'll be getting a good lesson in what bolt does what when you dial it back in my friend. It isn't fun at all but it's VERY important to overall focus of the image at the screen. If it isn't done right you'll see soft edges to the image, usually in one or more corners or the edges in the center. The tubes you DON'T mess with this on will show you what I mean.

Good luck and have fun. Take your time and stop back for help. If you get to a point you don't understand even after doing your own studying don't just keep going. Stop right there and ask the members here first.

[Sparky015]

To add to Greg's post, expect softness at the edges if you have stock HD8s on that machine. Just the way those lenses are. All you can do with schiemflug is make sure the softness is EQUAL on all four sides. Then you know you did it right. Just don't expect razor sharp edges like the center of the picture with those lenses. Good luck and have fun! Like Greg said, feel free to ask questions. Tim's site is great for how-to's, as is this site (Curt's).

[Francesco]

Yes, I have standard HD8 lenses... thank you for your information about the softness. And, since I know myself, an upgrade would be expensive?

Greg, thank you for such a welcome post!
I've read about the G2 wire and I'll make sure not to use the wrong pin. As per the G2 value do you think it's possible to reinstall the old blue tube so I can check the values and make some practice with the old tubes? I think that the projector won't be happy if I start it with just two tubes... and what happens if I do not reset those values before swapping the tubes?

Last question: where do I have to look for the P14 filament voltage? Is this correct?



img taken from here

How to lower the value if it's too high? I've read that the should be 6.35V at maximum.
If I understand correctly, one of the guys in that thread has made an extension cable (the red one in the picture) to check the value without opening the projector. Can I do the same?



And again, thank you all for being so patient and helpful with a newbie like me, it's a rare thing to find.