CurtPalme.com Home Theater Forum

[cmjohnson]

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[thewolfman]

Your right, I need to try this on old tube as I a few now. The rebuilt VDC blue, that went bust on me is the one I should try this on, it's to tempting to stay away from it. I need to know. But sure, most likely a bad idea.

Oh no, I forgot about the glycol spilling all over the pj if the tube goes to pieces. sh*t!

[cmjohnson]

If the tube breaks it'll be on the neck. No danger of a glycol spill unless you break the face of the tube, which is the thickest, strongest part. And very unlikely.

[thewolfman]

If you care to dissect, the inner parts of the tube back to front, that would help the reader to get an idea of what's inside and what it is suppose to do. Like why does the CPC need to further back. I get that the focus yokes have magnets in them and that they will obviously pull from the CPC, but if there' more to know I'd like to read it. Not that I will get much from it, but I'm sure there are more that share an interest to hear about it all the same.

[cmjohnson]

The need for stronger magnetics as you get closer to the face of the tube is twofold:

1: We don't want to deflect the beam to any significant degree until it has exited the tube bell,
where we now can, and must, deflect the beam across a large angle to draw the image on the tube face.
This requires a lot of magnetic field strength and it has to change rapidly and precisely to contro the beam
well enough to draw a high resolution image.

2: The closer to the electron gun, the lower the beam velocity, as the beam is accelerated toward the anode, and
the electrostatic acceleration force is weaker the farther away from the anode you are. Thus, the (relatively)
slow moving beam near the electron gun assembly can be affected by a relatively small magnetic force because it
is carrying less energy at this point. As the beam gets closer to the anode, (the CRT face, for all practical purposes)
the beam becomes more energetic due to its acceleration. And, in every real sense, the beam becomes more
massive as well, according to Einstein's most well known equation.

The CPC magnets are not string, in fact if you take one apart any ring out of a CPC magnet won't stick to a refrigerator. But it's strong enough to change the beam shape if it's near the electron gun.

If you were to attempt to put the CPC rings forward on the neck, first you'd probably wipe out the magnetic patterns on the rings
by exposing them to the stronger magnetic fields generated by the focus magnets and deflection yoke, but if they did survive,
you would discover that the CPC rings pretty much do nothing if they're forward on the neck. They aren't strong enough to do
much to the accelerating beam.


Here is a somewhat safe experiment you CAN do:

Build up a tube assembly with no CPC rings, and no focus coil. Install only a deflection coil, and
a separate convergence coil.

Being careful not to overdo it and throw the raster off the sides of the phosphor, see what happens when
you move the convergence coil across the tube neck. Slowly, not too much change at once.

I say to do this experiment with the convergence coil because it's safe to handle, voltages not being more than about 20 volts,
so it won't shock you, and it's not a massively powerful magnet but it's strong enough. It's stronger than the focus magnet,
actually.

The projector will still run. As long as the beam is scanning both horizontally and vertically it's OK.

One part of checking your magnetic alignment is to disconnect focus, astig, and convergence coils, to check the passive beam
centering and raster location. It's safe to run this way, just don't expect great focus.

You can also do the experiment using a focus coil instead of a convergence coil. You will be able to compare the two
and see for yourself how the different magnetic strength levels work at different points on the tube neck.

[thewolfman]

Thanks for the suggestions, I might give them a go some time. I should try them now while the pj is all opened up.

[thewolfman]

I've tried it now, and sadly the grid patter became about 2 inches thick, and I was unsuccessful to make it focus. So FY + stock yokes + CPC, does not work, and decided not try the other combinations either. Nah, all tucked together will have to do, and if any improvements is to be had, it'll be tucked together. To my relief, it didn't get worse doing that so worth doing the other two.



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[garyfritz]

[thewolfman]

I've finished forwarding the FY. Finally.

But I made som errors, I forgot that the 2010 deflection + convergence coils gives a greater warped grid pattern, and once that takes more corrections to iron out and leading to heavy banding. Last time it was the worst I've seen, so I will mostly likely have to change back to the older bits here.

And also, I discovered just now, with a reset pj, that I too have zaggies and have no idea how to get rid o them. Tjeerd might know, or I have traded down, maybe.

I made some changes to the camera, randomly, to better show the width of my grid lines, and hopefully, be able to look back at them laughing, when I set it up to hack standard. The best I can do.

I have only done RGB focus so far and it will be a nice treat to really make it right this time. A little lensflap, and the works, and it will be a nice pj I think.

Oh and, I've installed the MP VIM 03 now.


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[cmjohnson]

Those grid lines are nice and sharp. As for the zaggies, try different internal scan rates and see what happens to them. It can provide a clue as to where the issue is coming from.

[thewolfman]

I'll try that tomorrow, but not sure how I should go about changing internal scan rates. Anyways, I found several zaggies threads and I'm sure the answer is in there somewhere. It looks like I need to chase down a cip or two and swap.

http://www.curtpalme.com/forum/viewtopic.php?t=38792&highlight=zaggies

http://www.curtpalme.com/forum/viewtopic.php?t=39034&highlight=zaggies

http://www.curtpalme.com/forum/viewtopic.php?t=38851&highlight=zaggies

http://www.curtpalme.com/forum/viewtopic.php?t=38793&highlight=zaggies

[cmjohnson]

Select internal scan rates from source setup...I think.

I can't test it right now because all the LC assemblies from my projector are in a pan in the garage right now, being checked
for leaks until tomorrow. Today was glycol replacement day for my machine, first time since 2006.

I strongly suggest you spend time exploring ALL the menus and really get to know your machine and were all the adjustments and settings are located.

[thewolfman]

After resetting the pj yesterday, I ramped up contrast to 75, left brightness at 50 I think, where I usually have them, I forgot to set G2, so those got left at 50. Sorry everyone!

However, with nulled magnets, still, and G2 between 63 and 71 for all three colors, or there about, and everything else at 50, and an image roughly shrunk down to fit the screen, I now have grid lines that are 3 mm thick horizontally. I trippel checked on green, and really are that thin. But looking at it now, on image, RED appear to be even thinner, unbelievable. So it looks like it was all worth it. But if the vertical once are more important I'd like to hear about it. But a great starting point to set it up.

Unfortunately, I can't show it off with screenshots, as they get bloated like before, but took some anyway. And even if that feels bloated to you it was all worth it to me. So I am super excited right now!

And also, today I changed the CLM to my previous one, and now the zaggies are gone, but equally as sharp. I will remove the daughter boards, and change them between one another to narrow it down further, and until it's down single chips. I hope that will solve it. If not, I'll settle with an almost 2010 Marquee.

I took a picture of my two versions of CLM for the interested reader.



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[cmjohnson]

The smaller daughter board is the stigmator waveform board. If the zaggies still happen when the astig plugs are disconnected, you can be very sure that THAT board is not the problem.

[thewolfman]

So the wires going to the FGM should be unplugged? Or the wires going in the back?

Ah, I Googled it, the going to the back. I'll try that soon. Thanks.

[thewolfman]

I took some more shots - with astig - without astig - with G2 level at 50, like yesterday- and under normal conditions - and now the zaggies are gone all of a sudden. Very strange.

At the same time it got me intrigued to try and capture the width, and the core, which is pretty much all I see unless magnified with photos like this, and clocks in at 2 mm on the left, while I measured 3 mm on the right side earlier today. It all depends on how one decides to measure. I go for the core.

[cmjohnson]

Use a higher F stop number or a faster shutter speed or lower ISO setting to make pictures that are a bit less exposed, and thus look more like you'd see it with the naked eye.

[thewolfman]

I'll reshot them later, with the you suggestions you had, when I'm finished, I'm about half way thru. But can already tell it's a calmer pj. The faint horozontal lines are still there, but because the pj seem a lot calmer now, I only see it two feet away from the screen. Before I could see it from seating position if I looked for it. No, it does seem calmer alright. I'm glad I bought a 9518 too.

And even with heavy corrections, these 2010 parts have yet to give me signs of banding, unlike my first setup. But I have only half assed the geometry this time so that might change. Still much left to do. But every now and then I copy over to a second channel, in case banding suddenly appear, so I wont have to redo it all and just continue from there.

[thewolfman]

Let me start off by saying, that I brought Tjeerd's green LUG shot along as my personal reference. It's the first shot in this post, so don't get confused. He wont mind I'm sure.


Anyways, I thought it would be fun to document the improvements - or lack there of if that's the case - and shot some 1 to 1.

I just look at the lines, as I hardly know anything about it, but I think it looks better now when watching movies. The halos around those 3 digital clocks in KODI player looks reduced.

And those bloody clocks, look like they don't have any halos around them on screenshots, but they do, and my goal is to eliminate them completly. A clean digital look about it would be nice too see in this lifetime.

Shots were taken randomly with autofocus and manually and with random settings. But the pj has only been roughly set up and want to reshot these soon.

Red is notorious difficult to shoot but took a few and kept one.


1# Lenses needs to be refocused with obsession.

2# I need to learn more about setting magnets without any wires hooked up. I will copy the advice given in another thread. My first.

3# Astig still at fifty.


Tjeerd's LUG shot.


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[cmjohnson]

Got a camera with a live view function? You can use it to help you to achieve better focus than you can ever manage with the naked eye alone. Put it on a tripod, zoom in on the screen, see the grid lines with enhanced clarity on the camera's screen. Adjust for best sharpness as seen on the screen.