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Marquee Raster Height Issue

295 Views 13 Replies 4 Participants Last post by cmjohnson, Dec 18, 2005

jamieh

Discussion Starter · Dec 17, 2005

After patiently waiting for a mint green tube to come along for my 8000 it finally happened. Thanks to a previously made contact here on the forum and fairly local i aquired a rough looking chassis but with nice clean tubes. After a few card swaps i got it fired up and the drive levels and run hours checked out nice. Ran it for 3 hours on the bench....no lenses. Yesterday i decide to transplant the green tube complete with undisturbed magnetics into my own machine. The only part i changed on the donor tube was the neckboard. Fired it up ,,,started no problems and did a total reset. Restart the pj again and went right to the setup. Now i have a problem...when trying to match the heights of the colours the green is a bunch taller than the red and blue...enough that i almost have to max out the adjustments. Everything else went fine until i noticed the pic seemed pretty tall. I ran my vertical size right to zero under my size adjustments and still can't get a proper looking pic height wise. This 8000 never had the anamorphic mod done and i felt i didn't need it because i always had enough adjustment to display a proper size picture to match my source. Other than this its running sweet...green is nice and sharp now,,,contrast 35 brightness 38. DVE was used for initial setup.

Any suggestions people?

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Tim in Phoenix

· #2 · Dec 17, 2005

Sir

You need to match red and blue raster heights with convergence nulled, push UTIL, 9, 0901, 3 for that. You also need to match raster widths, get a 0.10" plastic hex coil tool at RS and have a look here:

http://www.etechvideo.com/techtip9.htm

The server is down at the moment, try back later.

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jamieh

Discussion Starter · #3 · Dec 17, 2005

Tim

Thats were i attempted to match the heights. When in that menu and prior to making any adjustments the green is a good 6 to 8 inches taller both top and bottom. Needless to say once i adjusted the red and blue heights i nearly ran out of adjustment reaching the green. I did start with convergence nulled. Raster widths are nearly identical even after a reset.

Jamie

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Tim in Phoenix

· #4 · Dec 17, 2005

Hmmm

That is weird; the green scan yoke could be the wrong version, or perhaps it has a lot of glue in front and is not fully forward, have a look in there or pad the gap between yoke and glass for red/blue to get a match. If this unit was modded for anamorphic perhaps the resistor values are off; confirm values as shown in Tech Tips at http://www.etechvideo.com/ The server may be down for a while, keep trying.

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jamieh

Discussion Starter · #5 · Dec 17, 2005

Perhaps my best choice would be to take the scan yoke from the original tube and put it on this replacement. I did remove the magnetics cover plate on the donor tube and it seems like there is a hell of a lot of hotmelt glue on and around the tube and yoke....more than i have seen on others. How far would the yoke have to be away from the tube to start having an influence on size? I would also assume that it would make a difference in both the horizontal and vertical size. Thats why i'm puzzled as my problem is only on the green vertical.

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Tim in Phoenix

· #6 · Dec 17, 2005

Sir

Take extra care removing hot glue, we use a 2" Exacto blade heated by a small torch, I manage to nick the windings and ruin one yoke in every ten.

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jamieh

Discussion Starter · #7 · Dec 17, 2005

Was hoping somebody might have some suggestions before i try pulling off this overdose of hotmelt glue.

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draganm

· #8 · Dec 17, 2005

lets start with a little more info, what production year is your machine and hwat year whas the machine the tube came out of? The yokes can be very different , especially if it's between like 1993 and 95.

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jamieh

Discussion Starter · #9 · Dec 18, 2005

My machine is a Jan 95 8000 and the donor machine was a Apr 94 8000

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draganm

· #10 · Dec 18, 2005

hmmm, well that's a tough one. I just took apart a mid 93 8000 and early 9500 8110 and the yoke's were different. Not by casual osbervation, they were the same size, connectors, etc. But if you looked at the windings undrneath, the newer coil was a lot different. The older coild use a much thicker gauge copper wire and fewer of them. The newer coil is a much finer winding and has more individual strands. They're also a different color so the copper alloy composition migth have changed too? If the heights are that different, you haven't plugged anything in wrong and blown an amp somewhere (convergence and geometry work right), then I would take a look at the coils.

Personally, I don't use any kind of knife, loosening the clamp on the convergence coil and giving it and the sweep yoke a good twist will break them loose from the glass bell.

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jamieh

Discussion Starter · #11 · Dec 18, 2005

I,m going to strip that donor tube down and install all the magnetics from the original tube. I,ll keep an eye open for any differences in parts and i'll watch for what you mentioned. Everything works perfect on this machine except for the extra height on the green.

Jamie

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cmjohnson

· #12 · Dec 18, 2005

I've probably pulled the yokes off of maybe thirty Marquee tubes so far and never once

have I had to use any tools to do it or damaged a yoke. A few gentle twists, one way

and then the other, will safely break the glue bond without damage.

Can you give us the part numbers of the new version yoke with the finer windings, please?

I want that info for reference.

I'd try swapping the vertical deflection module and seeing what happens to the raster heights. I'd be more inclined to wonder about the yoke, but the vertical board is usually

easier to swap out than the yoke, all things considered. (Full magnetics alignment...it's

a minor pain even when you've done it a few times and have a handle on it.)

Better yet...leave the VDM in place. Just trade the vertical deflection wiring harnesses between the green and one other tube, where they plug into the VDM.

If the same tube continues to have the height problem, it's not the VDM that's at fault.

CJ

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draganm

· #13 · Dec 18, 2005

chris, the numbers I have for the convergence coils are 9260.01 for the older and 9260.04 for newer. Take a look at the 2 convergence coils, one on the left is from 93 & early 1994 machines. The newer coil is on the rigth and is found on late 1994 and newer machines.
http://tinypic.com/view/?pic=iqh449

BTW, the sweep coils look almsot identical, the actuall coil wires are a litle different but the at least the winding is the same pattern. I would bet money it's the convergence coil that's actually causing the difference in geometry. I mean how can it not, a different shaped winding HAS to produce a different EM field!

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cmjohnson

· #14 · Dec 18, 2005

I don't quite know about that. No doubt the coils are different revisions, and there must have been a reason for the change, but I can't say why.

CJ

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