CurtPalme.com Home Theater Forum

[pm]

Thanks for the replies to my previous (multiple!) query, the bottom line was that I was asking too much of the bandwidth needed for 1920x1440.

I now have more questions! I have real problems down the left hand side of the screen in the form of the horizontal lines having a "wave" or "squiggle" in it and the blue grid rotated by comparison. Hopefully the pictures explain better than words.

I have started from square one. e.g All blocks deleted. All adjustments reset to mid position. SMPS tweaked for 17.5V and the Q3 collector checked at 48V.

This is how my test card looks before any work done. The red and green very similar but the blue is rotated left side down by comparison. Also, the wiggle on the left hand horizontal lines can be seen. The top left hand corner is even more marked.





I can converge the tubes but the left side remains distinctly blurry by comparison. I've tried the horizontal linearity pot as well winding the horizontal width up and down.... all to no effect....

The only way I can get good focus on the left side is by winding the resolution down to 1280 x 720.

Is there anything else I can try in order to get 1920x1080 without issues down the left side?

Cheers,

Paul

[opv]

Try playing with H shift on the geometry menu.
What is the frame rate of the input? is it 60Hz?
If so, you have to make sure that the projector goes to high scan mode.

[Ile]

Have you checked that there is least 15mm unused raster at left side before actual picture start?
Remove blankings, lower contrast to 10, elevate brightness to 80 and look to tubes face.

Can you see raster ringing (electron beam waving forms vertical bars near left edge) with light gray field?
This is caused by same problem.

Electron beam needs time to stabilize before actual picture start with high resolutions.

-Hphase moves picture inside raster, if there is unused raster at right to use. Then compensate with raster sift to get actual picture centered.

-High scanning mode might help little to this problem. Tweak horizontal deflection sub board pot P64 to get it on, if it's not yet activated. Green led on same board lit when it's activated. P1 on horizontal deflection board is also for horizontal linearity, but shouldn't have much effect to this high. It's meant for 18kHz range. Same thing with linearity coils core at same board, it's meant for 15kHz.

If these actions doesn't help to get enough unused raster before actual picture, chance your sources horizontal back porch bigger to get more unused raster. Sources default resolutions have timings made for digital displays, so porch settins need to make bigger.

If you doesn't have scaler or pc as source, there's no way to chance timings.

Don't know hardware fix for this, but have hunch it might be width coil related.
I have been thinking to remove those to see what happen.

Have you adjusted Sheimpflug to be sure that left focus issue is not optical issue?
Good to check, even I don't think it's causing this.

[pm]

Thanks guys for the comprehensive replies.

I had been trying to maximise phosphor use but was quite careful not to overscan the tube face. However, I will go back this evening and check how much margin I left and increase it further.

I do use a PC exclusively. It did cross my mind that it may be a graphics card issue. However, a different computer with a different graphics card soon dismissed that idea. I only use W7's basic functions as that had been enough but I'll revisit Powerstrip again and try some different settings.

Should reducing the refresh rate (and the bandwidth) make much difference?

I'm pretty sure it's in high scanning mode, but again I'll check later.

The whole blue pattern seems to be worse affected than the others. Is there any particular thing that will affect one tube more than the others?

It's definitely not Sheimpflug or optical focus, that's the one thing I am sure about!

I'm pretty sure that, old burnt tubes aside, I've got the basis of a good machine. I can get excellent mechanical aiming sorted before converging begins and that means nearly all the electronic converging is done in the range +/- 10 of mid point settings. If I can get this left issue sorted, I'm feeling enthused to think about re-tubing the machine.

Paul

[opv]

From my experience with 1209s,
You have to use custom timing using powerstrip or a VP, to get a decent 1080P geometry.
That's not the case with all CRT models, my previous 808s was much less sensetive.

[Curt Palme]

That wiggle is very common on 1209s, and to date I haven't figured out what it is. Next time I get a G1209s in, I will experiment again to nail it, it's been at least 2 years since I've had a G1209s in though.

[Curt Palme]

That wiggle is very common on 1209s, and to date I haven't figured out what it is. Next time I get a G1209s in, I will experiment again to nail it, it's been at least 2 years since I've had a G1209s in though.

[pm]

[pm]

Thanks Guys,

I appear to have got there..... A combination of Powerstrip and winding the refresh rate down to 50Hz seems to have done the trick.

The scan rate is down to 56kHz which appears not to drive the board into the high range and now the left side is much more manageable.

The slight wiggle persists but it does converge. The left still doesn't focus as sharply as the right which is disappointing, but it's now a very watchable picture.

[opv]

Are you sure the picture is centered on the tube? it looks like the left side is very close to the edge.

[fragzero]

[pm]

[fragzero]

I have no idea, all i know is:

- Low range = long retrace time
- High range = short retrace time

I'd search for information regarding retrace time if you want to know more.

I also noticed porch timings have a huge influence on the top left corner, i had it I once had an issue with 1080i. Couldn't get it right untill i noticed my porch timings were very small (Lumagen HDP), once i added 50 pixels no issues at all.

[pm]

[fragzero]

I think it's called P1 or P2 but can't recall on which board it can be found