CurtPalme.com Home Theater Forum

[Robert A. Hill]

Does anyone with a 3600 or 4600 have a hard-wired jumper between the reg board (81435) and J3 on the focus modulator board? I do not have it on either 3600 I have, but saw it in the service manual. I cannot see any other connections that could take the place of this jumper. I do have registration boards from 3300s that have this jumper, but they are not #81435.

Also, when adjusting the focus phasing per the service manual (section 9.5.11.1), you are supposed to adjust master horizontal skew all the way up, left red skew up and right red skew down. Then you adjust R4 to minimize distortion (bow) in the red horizontal line. When I do this, the cross hair is not centered at all. When adjusting R4 so the cross hair is close to center, I have a lot of distortion in the image. Can I get the cross hair centered and the distortion minimized at the same time?

[stefuel]

I can't answer the rest of the question but I'll go out and check the 3600 that's hanging in the garage for the jumper. With any luck tse will answer the rest.

[tse]

The wire going from the registration bd to the focus modulator (usually a purple one) carries the vertical parabola that is used for top and bottom focus. Does your vertical focus modulation work? I just checked my VDC 3600 and it has the purple wire. I don't think the signal was ever connected in any other way.

The adjustment that you are making with the skews adjusted is for the registration phasing, not the focus modulation phasing. You really need a scope to adjust the focus. R4 is for registration, R44 is for FM. One of them has to be adjusted first as it effects both, then the other can be set. I don't remember the sequence.

Scott

[Robert A. Hill]

TSE,
What is the connection point on the registration board that the purple wire connects to? Any danger in attaching on to see the effect? Dynamic focus is working, but I'm not all areas in sharp focus at once using static or dynamic controls. I've already done the CPC magnet adjustments and get very good results in the center, but can optimize either center or corners- not both.

[tse]

The V BOW test point on the center section of the registration bd is the origin of the vertical parabola for the top/bottom focus modulation. The vertical modulation is obvious when working as it has alot of range. Proper amount of modulation is only 20-30% of the total available.

I modified my projector just slightly by connecting a 100 ohm resistor to the test point then connected the wire to it. The factory didn't bother but it is the proper thing to do.

Remember that when adjusting the dynamic focus it only valid in the center of the top/bottom side and the horizontal really only adjusts the half way down the left and right sides. The adjusments aren't corner adjustments.

[stefuel]

Now I have to go and look. I have 3 complete running X600 projectors and don't recall ever seeing the purple wire.
I'll be back

[stefuel]

Non of my projectors have the "purple" wire. On the focus modulator board, "J3" is a 2 prong connector next to R7. The prong closest to R7 is connected to R7. The other prong appears to go no where. I have noticed that I get little control over top/bottom electronic focus. If I were to add the jumper with the 100ohm resistor, would I gain more control over that top/bottom area? If so, what guage wire do you suggest? Thanks,

[tse]

Hmmm. Just because I don't remember that signal being routed any other way doesn't mean it didn't happen. The vertical modulation should obviously change the top and bottom focus when adjusted min to max. If nothing is happening it might not be connected. I think my 3600 is the latest revision as almost all of the bds are VDC bds and the vpara (V BOW) signal gets to the fm bd via the flying lead from the registration bd.

Scott

[stefuel]

Well, the 3600 hanging in the garage is my test projector What's the worst that could happen if I took a alligator clipped jumper wire and test it?

[tse]

Make sure you connect only to the pin that R7 connects to. The other pin might be ground and that could damage a chip on the registration bd. That's one of the reasons for the 100 ohm resistor on the TP. If the wire gets connected to something bad there is alot less chance for damage.

Scott

[Robert A. Hill]

TSE,
Thanks for clearing up that dynamic focus is only for the centerline (Vert and Horz). Are there any adjustments for the corner vs center focus or is static focus and magnetic adjustments the only ones?

Stefuel, I attached a jumper to the V-Bow test pt on the reg. board and J3 (focus board) and saw no change in dynamic focus range, but my PJ had a lot of range before I did this. I left the jumper in place since it appears to do no harm.

[stefuel]

I like blowin $hit up. This will be fun

[macgyver655]

[macgyver655]

[stefuel]

[Robert A. Hill]

On the screen and using a crosshatch pattern, I cannot get even line width over the entire area (center and corners). I'm running 720P but I also see this on the internal patterns so I do not think it is source related. KennyG had issues like this with his Ampros a few years ago and I don't know if he every resolved it. (He eventually went to the grey side)

I can optimize optical focus with the lens adjustments for center and corner using the focus knobs and Schlemplug adjustments. I have very good looking dots (in the center) with the magnetic adjustments. There is no movement when I change focus so I think beam centering is correct. However, the entire screen does not change focus evenly when I change static focus (in or out). I have very sharp lines (or other features) on most of the screen and this makes the corners look worse than it would if the image was blurred overall.

As TSE explained, the electronic dynamic adjustments do not control the corners and I cannot see anything that would. Maybe what I'm seeing is just due to aging tubes as these have a few thousand hours on them now.

[macgyver655]

[tse]

No, there is no dedicated corner focus. But, if the top and bottom dynamic focus is correct and the left and right dynamic focus is correct, the corners will be VERY close. What won't be close is the corner 'stig. There were plans to add dynamic 'stig modulation to the Ampro chassis but it never happened. Only the static 'stig (center) can be adjusted.

It helps alot to use smallish text to focus the dynamic zones. Top center, bottom center and left center, right center. The left right benefits from having the dynamic waveform phase set correctly.

Scott

[Robert A. Hill]

Mac,
Thanks for checking and motivating me. I checked my setup using the test pattern genlocked to my 720P signal like you did. The corners were much closer than I was seeing with the HTPC pattern. Then I noticed that I did have drift when I changed focus on the red and green tubes. I readjusted the astig and flare and now the corners are in focus at the same time as the center. I cannot believe how much effect a minor amount of error in the magnetics had. I only tweaked the magnetics very little from where there were to eliminate the focus drift. I actually could not see any difference in the dot shape, but could see the movement much better.
I finished the dynamic focus setting like Scott said using text and changes were much more apparent also.

Thanks guys! My image has never looked this good.

[macgyver655]

Glad everything worked out for you. Enjoy