CurtPalme.com Home Theater Forum

[backslap]

Hey guys,

I just got myself a Marquee 8500 Ultra with HD 144 lenses a week ago to replace my old Sony 1251. The improvement is dramatic! But after a week of tuning I have a small poblem with it I haven't been able to resolve:

As can be seen clearly in the picture below, I'm having trouble focusing the red tube on the left side of the screen. The projector is about 106" away from the screen. The angle is about 14.5 degrees. The other tubes are focusing perfectly. When I slide the PJ a foot away from the screen and re-focus, the problem almost disappears, but at the cost of 18% lumens on the screen!

I have properly setup the PJ mechanically / optically, adjusted the astig electronically and adjusted focus electronically and the problem remains. What I did see is that when focusing electronically, the red tube's focus on the left side of the screen was set to 0 and moving it up the scale didn't produce any improvement!

Could this be a problem, solved by adjusting the convergence timing?




Grtx, Elwin (The Netherlands)


EDIT:


I think I need that super secret password, wouldn't you guys agree?

[garyfritz]

No, the convergence timing is something else.

Are you sure you have the Scheimpflug adjusted right? With proper mech setup, that's the most common cause of side-to-side focus issues. Though I wouldn't expect that to go away if you move the projector.

I assume the lines are sharp on the tube face?

[backslap]

Hi Garyfritz,

Looking at my EDITed pictures, wouldn't you agree that my convergence timing is way off?



I have the scheimpflug adjusted the best I can get it. I have also tried adjusting it with the 'factory' bolt at different settings but there's no improvement.

The image is sharp on the tube face.

Grtx, Elwin

[Nashou66]

Yes your timing is off but what the hell is the distortion on the bottom right? i have never seen that before!!! Looks lik it is on all tube correct? is it there on the tube face with the lenses removed?

Athanasios

[nuttall_chris]

If the image is sharp on the tube face than scheimpflug is the problem. Also, yes your convergence timing is off.

Chris

[backslap]

Ghehe, the smudge is built in to my phone camera!

But is the scheimpflug is off, how could it be I can't get it correct? I have tried to do it several times, also, like said, with the factory screw in different settings...


EDIT:

Also, Cmjohnson, 1st post:

[cmjohnson]

That is absolutely and definitely an issue with convergence delay timing. Anyone who thinks it's something else is wrong.


CJ

[garyfritz]

Seeing your additional pictures, yes it looks like your convergence timing is off. I defer to Chris for the effects of convergence timing. I'd never heard of it before this thread. If he says that'll cause it, he's the expert.

And I need to check the timing on MY projector!! I have some similar focus issues that I THOUGHT were Scheimpflug....

[backslap]

Chris, thanks for the Super Secret Password!

I have green centered on the '41' mark, but... Red is still a little off!

Should I adjust so that they are both as good as possible, or just optimize green instead?


Ragards, Elwin


EDIT:

I see now that red is not off. It's just off at the edges of the screen, but so are green and blue. Convergence timing is now set! Thanks!

[Ile]

[Nashou66]

I just did the green, it should follow for everything as it should be a global timing pulse that gets divided for the rest of the convergence board id think, I need to read the service manual for the theory of operation.

And Gary, now that I think of it after i did the timings it did seam like my edges did become a bit sharper, the blend zone converged better for sure, even on the vertical plane.

Next i will try the focus timings only after I get my new Hurley screen up and redo the optical and CPC magnets. Chris, what would the progression of focus be ? Do the Optical, then CPC, electronic, timings, then do it all over again?

Athanasios

[cmjohnson]

Your guess is as good as mine!


Optics, magnetics, software adjustments. Repeat as necessary.

I'd center up all software adjustments first. Put them at 50. Align the magnetics so they're centered in the optical path, and the optical
path centered on the screen. Then adjust the magnetics and then make software adjustments on focus and astig.

Of course you'll want to make more than one pass.


CJ

[garyfritz]

Sure enough, my timing is off too. Hard to believe I never noticed that. It looks even worse than backslap's. Chris, can you initiate me into the sooper seekrit handshake club?

I have some rotation in my red yoke too, but I knew about that. I got lazy and never fixed it because I didn't think it would really hurt anything. Chris, does a bit of rotation harm the image once it's converged, or does it just make it a bit more challenging to converge properly in the first place?

[Nashou66]

FIX IT !!! Think about it Gary, lines that should be vertical are now
off a bit allthe way down . It be like each pixel is skewed a bit.

Nashou

[dturco]

Ok, Now you all have me wondering.

So Will someone P/M me the Super Secret Pasword, so I can have a look see.

[CRT_Ben]

[Nashou66]

[cmjohnson]

Rotation should be addressed. The more mechanically correct your setup, the more stable it will be electronically.


If you want the passcode, PM me.

Or, here's a clue:


2548253505625


An intelligent person can easily get to the "root" of the cause, particularly if he's well squared away.





CJ

[garyfritz]

Gotcha. Thanks Chris, I won't be able to get to this until at least next week, but I'll definitely look at it. Rotating the red might take longer.

[Nashou66]

Uh oh! its out there now, Only the CRT gods know what troubled times this may bring.....


Dave stop looking for your calculator!!!

Athanasios