CurtPalme.com Home Theater Forum

[redfox001]

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I am trying the focus yoke of my 909 in my 9500 and have the following problem.

The static focus vertical needs to be set 100 and it still is not focussed.
The dynamic focus horizontal seems to be in focus right away.

I moved the yoke as much forward as possible moving it backward made the focus worse.

When I measured the resistance of the static vertical yoke I measured less than 1 Ohm while the Thomson measured 41,3 Ohm. I tend to conclude this Barco 909 yoke is not compatible at all. Am I doing something wrong?


The dynamic horizontal windings also measure less than 1 Ohm.

The image was turnes 45 degrees. Could reversing the magnet in the house be a solution?

[redfox001]

This is how the pins are related:

Now because static focus is vertical and dynamic focus is horizontal I came on the following pin mapping.

I came to these pin numbers by looking in the schematics and a little number is written next to the connector symbol on the Marquee docs for focus and astig. With the Barco there was a layout of the motherboard.

marquee: barco 909
focus
p101

pin1 = R-DYN-H pin7
pin2 = R-DYN-L pin9
pin3 = R-STAT-H pin3
pin4 = R-STAT-L pin5
pin5 = R-TEMP-L earth pin1 ?
pin6 = R-TEMP-H

astig
p2
pin1 = RY-STIG-L pin2
pin2 = RY-STIG-H pin4
pin3 = RX-STIG-H pin8
pin4 = RX-STIG-L pin6

barco cine9:
focus and astig

J155

pin1 = earth

pin2 = 4PYL-R
pin4 = 4PYH-R
pin6 = 4PXL-R
pin8 = 4PXH-R

pin3 = FVH-R
pin5 = FVL-R
pin7 = FHH-R
pin9 = FHL-R

pin10 = 6P
pin11 = 6P
pin12 = 6P
pin13 = 6P

[barclay66]

[redfox001]

Ok but I can not get the center focussed.

The strange thing is that I now try the sony 1292 coils and they measure something like 52 Ohm but still I need to go to 100 in the global focus and not sharp.

I must be doing something wrong perhaps turn the coils in the housing?

[redfox001]

My mistake. I had the high and low pins reversed. I compared with the doc that was posted here. Perhaps there is a reason to reverse the pins so you do not have to tunr the inside of the coil? Or are the schematics just wrong? Goog thing these Molex pins can be changed easily

I had
1 = 7 2 = 9
below
2=7 1=9
etc.

[barclay66]

[redfox001]

He seems fixed.

The grid is turned 45 degrees with the coil and that seems to be because the permanent magnet is reversed. Anash advises to leave it this way but probable reverses the pins on the coils.

I wonder if I will simple reverse the inside of the coils as I already opened it. Any advise someone?

[redfox001]

Ok results so far. The 909green yoke works but he others have to weak magnets.

The 1292 yokes work better again not completely the same. The result is that I now have the contrast lower and still have the punch or more light. The control over the beam feels better and without centering problems I find it easier. I had the green astig done in half an houre and see now the different lines in the 1:1 pattern very clearly.

Seems the longer yoke diffuses the beam less as there is more concentrated light. About blooming I did not see that much before with the mp boards do not see much after certainly not at 70 maybe at 90.

[redfox001]

One question for CMJohnson.

Do you have the equipment to magnetise focus yokes?

My center focus vallues are 28R 31G 28B These are somewhat low. If remagnetising would make them 40 that would be nice.

[cmjohnson]

Tse is the ONLY person who visits this forum who currently has access to the only known (that I am aware of) magnetizing rig for focus yokes.

I would suggest you contact him and see if he is willing to adjust your focus yokes to an optimal magnetic strength value.

[redfox001]

Thanks for the info!

One other question. Yesterday I tried the focus as good as possible and found out I have to little range at the static bottom side.

My midpoint focus is around 20 on that one and 0 is to high at the bottom. The other 2 just have enough.

Did you experiment with removing the ring from the convergence yoke to get the focus yoke more forward?

I am now thinking of setting this one on blue.

[koldby]

Aparently all the pictures of the original frankenyoke MKI and MKII are missing...
Can this be fixed??

Koldby

[koldby]

Has anybody tried yokes from Barco 1209s?

[redfox001]

I have tried 809 those did not work.

[nidi]

[Curt Palme]

If anyone is interested, I do have at least one set of G90 yokes in stock that I'd sell cheap.

[Curt Palme]

If anyone is interested, I do have at least one set of G90 yokes in stock that I'd sell cheap.

[redfox001]

[jbmeyer13]

[redfox001]

Taking them backward? How odd all yokes I have tried needed more forward.

[cmjohnson]

No, I can't do anything about the broken photo links early in this thread. Those photos are gone, lost in my OLD computer which has long since been retired.


Just to review a few basics about yokes, to help with your diagnostics:


Install a stock Thomson yoke on your green tube if you don't already have one. Disconnect all plugs on it and see how well focused your picture is.
What you get is due to the static magnetic field only. It should not be perfectly focused. But it shouldn't be THAT far off.

Now, disconnect a dynamic winding from the focus yoke. Pull one of the pins out of the connector with the aid of a very small screwdriver.
The two central pins are for static focus, so you'll remove (sorry, I forget the color code) one of the two lead going to the dynamic coil.

Now plug the focus coil back in and adjust your focus setting until it looks the SAME as when you unplug the coil. Make note of this value.

Now adjust for best central sharpness, and make note of that value.

Reconnect the dynamic winding and now adjust dynamic focus for best results. Note the values.

Ideally, the "same as unplugged" value should be between 40 and 60. (I'm thinking 60 is what TSE said is optimal.)

Plugged in, it should take an adjustment of no more than 10 to achieve sharpest center focus. With a yoke that has optimal parameters.
Now, run the focus range from 0 to 100 and back to best focus and make note of how much this affected the size of the grid lines.

You can repeat this process with the astig windings as well, but do CPC ring astig adjustments first.


In order to evaluate an alternative focus yoke, repeat the above test and make note of the values you get.


The first thing this series of tests will tell you is if the strenght of the permanent magnets in your candidate yoke is even appropriate for the application.

The second thing this will tell you is if the static windings are effective and if they have adequate range or if they have too much range. You don't really want them to have more range than stock yoke static windings do. With too much range you'll lose fineness of adjustment when you're nearing the range of best focus.

The third thing this will tell you is if the static windings are effective and have adequate range. Same rules appliy as to the static windings. Use the Thomson yoke focus range and values as your general target.

And of course, the fourth thing you'll learn from this is how well the electronic astig windings work.

If passive magnetic focus isn't in the right range, static focus won't fix that. If static focus can't make it right, dynamic focus is irrelevant. And if it's still wroing, who cares about astig?


The path to optimizing a yoke for a Marquee is to first check and adjust passive focus which usually requires magnet strength adjustments. Unfortunately,
very few people have the capability to do that. With passive focus being in the right range, then the static focus coil needs to be evaluated, and if it has too much focus capacity, take a few winds off it. If it lacks enough capacity, carefully unwind it and count how many turns are on it, and then rewind it with new wire and add on extra turns, retest, and repeat as needed. Then address dynamic focus in the same way.

Odds are that due to the way the astig windings are made, yoou won't mess with them. They'll probably do the job in any event.