CurtPalme.com Home Theater Forum

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Most of the stuff I've read on this site makes me believe that scanning off the face is never to be done because of the risk of overheating the glass, yet some manuals describe doing so as part of the setup. I suspect that it's no big deal for very short periods of time but how badly do we want to know how far we can go with doing so.
If you work with something full time you tend to get away with things that other people wouldn't just because of familiarity and a sense of what really does matter.
On large motor starters we are taught not to file the contacts. I had an older gentleman from the factory out to a jobsite once upon a time and the first or second thing he did was get out his file. He looked at me and said " you know how the dentist tells you not to use anything abrasive on your teeth and when you go to him for a cleaning he uses abrasive paste? Well I'm the dentist"
I wonder if you can use the blanking adjustments to keep the action on the face of the tube.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Right ray. s long as a full white active image is not projected on the side glass it will be fine. The raster should be black anyhow
for a good black level. even if it is lit to about a 5% white level it wont hurt it unless you leave it on over night.

and as you said you can use the blanking to cover the raster up to the active image.

This is what I do. it also helps with any haloing and contrast ratio on the edges of the image.

Nashou

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

I've gotten 8500's with the tube face burnt and the burn extending right over the edge of the glass face onto the bell. Marquee tubes are tough, much tougher than the imploding P16's used on the G70 and PG's/XG's, although those are really rare too.
I don't recall ever hearing of an imploding 9 inch except maybe from really high glycol pressure or the PJ being dropped and neck cracking.

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

It's hanging from the ceiling now. The manual does a terrible job of explaining how to reverse the scanning. but the markings on the plugs make up for this.
To get the image centred on the screen vertically ,the pj is now tilted up at the front to raise the image. This puts the face of the CRTs more parallel to the screen but defies the objective of keeping the pj level.
Did I do something different by hanging it from the ceiling AND having my screen go all the way to the same ceiling minus a 4" frame/border?
And BTW Curt, You must have set it up at about the same throw 'cause it's pretty close without starting to do the convergence.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

yeah thats too close to the ceiling. Usually the top of the screen should be the same height as the top of the lens or a couple inches below them.

Nashou

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Will it hurt anything?
I mean the front of the pj is that much more parallel to the screen.....less keystone?

I had the opposite situation with the AMPRO : the front had to be tilted down.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Should be fine as is it will just look strange tilted up.

Nashou

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

FWIW it doesn't look all that strange. The line of the projector that's most visible is the cover.
Makes sense to me to maximize screen size rather than buy a bigger house to have some extra space on the wall above the screen.
Not on my budget!!!!!!!

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

If not for the pj being in the way,wouldn't the ideal be to have the face of the CRT parallel to the screen then keystone wouldn't be an issue?
I assume that the tilt of the CRTs relative to the case is a practical angle but with the back tilted down on a ceiling mount the faces are closer to parallel ?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I think your fine Ray. Less Keystone and I am all for going as big as your wall allows Wink

Enjoy!

If you ever need help i'm just a short drive away.

Nashou

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

**AnalogRocks** · Posted: Tue Jan 07, 2014 12:04 am Post subject:

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

The screen is painted onto the drywall. The lens faces aren't dead parallel to the screen, just not as tilted as when I had my level lying on the base

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

I used the crosshatch pattern(#) to centre the image and find a practical throw distance. ie) almost full crt face/ full screen. The guided convergence is great, only weird thing is:
the test pattern for the convergence is bigger than my screen. Some of the adjustments at the left edge and at the bottom are smeared onto the wall.
Shouldn't the test patterns be the same size?

If I can see the entire image when I look into the lens, I can't be overscaning the face of the tube, so is it possible I've sized the image to a shadow rather than the edge of the face?
This would make sense If the size adjustments had less affect on the guided setup pattern.
Rolling Eyes

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Got the bit with the test patterns figured out.
Thanks

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Can the electronic focus be adjusted separately for each colour?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Thanks
I downloaded and printed the training manual
That helps.
I just went through the focus and converge.
Convergence is kinda fun compared to the Ampro.
The focus is hard to get just right: Center focus/edge focus/scheimphlug/static/dynamic. I think I've got the sequence figured out.I believe I should adjust to see the individual bits that make up the lines.
While wading through this and trying to get each element in the crosshatch clear for each colour, I get the occasional "jitter" and the pattern moves down about 8 inches, and then back to normal. I see arrow heads travel about halfway down the screen down the vertical lines in the crosshatch. At the best focus I can achieve (still a little fuzzy) I can see what this machine is capable of. I can see briefly the little pattens that make up the lines of the crosshatch. I wondered if maybe something loose ,but no response to the normal test for something loose ie) tap/slap
I know I should warm it up better before I do the setup so I'm wading through a couple times to get familiar.
Should I shrug my shoulders and run for an hour before setting up; that would mean that after setting up its going to look strange after a good setup? Rolling Eyes

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

OK "Jitter" seems to have disappeared after leaving it on for a while. Maybe electronic noise from something else nearby.
The manuals for these machines is laid out as if the writer kept thinking of something else he should tell the reader instead of in order of the steps to properly set up. I know that's normal for most tech literature.
Thanks, but am I going about this wrong? I set the electronic focus to 50 for each zone,each colour. Then adjust rear barrel for best focus at centre. Then the same for corners, then defocus the rear barrel and balance the fuzz top to bottom, then side to side, then put the centre back to best focus.
Shouldn't I be able to get the centre, then each zone sharp? I mean isn't that the point of focus?
Then tweak with the electronic focus?