CurtPalme.com Home Theater Forum

[andreas]

Hello! im starting a new thread so i wont spam the frankenyokes thread.

Like the picture shows,is this the right way to grab hold on the yoke and then twist it by hand? should i peel of all of the glue marked on the picture? the contrast should be at low levels i guess.

/ andreas

[Curt Palme]

I would slide a small screwdriver under the glue. Most of the glue on these yokes will loosen once you twist the yoke, but I've sheared off a couple of wire loops on a couple of sets when the glue doesn't loosen. Make sure you don't shear the wires with the screwdriver though.

Worst case, I've got a pile of spares, so no worries there.

Also, there's 800 volts on the H yoke windings, so maybe wear gloves when you rotate the yoke..

[Curt Palme]

I would slide a small screwdriver under the glue. Most of the glue on these yokes will loosen once you twist the yoke, but I've sheared off a couple of wire loops on a couple of sets when the glue doesn't loosen. Make sure you don't shear the wires with the screwdriver though.

Worst case, I've got a pile of spares, so no worries there.

Also, there's 800 volts on the H yoke windings, so maybe wear gloves when you rotate the yoke..

[Nashou66]

Dont grab the Yoke itself unless you want a nice static shock!! I just grab the wires around where the tape is and move them that way.

Athanasios

[barclay66]

Hi,

Three of the locations in Your picture should be left alone as they are part of the yoke itself. Only the glue between the tube and the yoke should be loosened...

Regards,
barclay66

[Tim in Phoenix]

Guys

Unfortunately the Electrohome assembly people put absurd amounts of hot glue on many scan yokes. It is between the front of the yoke and the bell shaped glass, and it is fiendishly hard to remove without ruining the windings. I have had some luck with long thin Exacto blades heated with a small torch. There is no need to turn the scan yoke unless it is seriously off of level.


.

[mr_ro_co]

[Tim in Phoenix]

[andreas]

good tips! i have managed to adjust them thanks to all your tips. Good thing i did not peel all the glue on my picture of then. It did have a impact on the magnetics so i had to do the cps magnets again... I will wait till darkness falls to fine tone.

steve! how is it going with your focus yokes?

[mr_ro_co]

Andreas,

Nash is going to scold me for not putting this in the frankenyoke thread. All in good time, as I am documenting this!

I have the G90 yokes in the projector. I am connected black->green on the static coils and I have experimented with polarity on the dynamic coils too but stayed orange->red. I have tried physical orientation "normal" and "flipped." I currently have them all with the static coils facing the convergence yokes. I have experimented with position along the neck and with rotation. While the red and blue show good promise, the green is being problematic. I cannot seem to get good side focus, especially on one side (I'm worried the magnetism is degraded). I have been moving the yoke along the neck and going back and forth between center, side focus and dynamic stig trying to find the "sweet spot," but haven't found it yet.

As I'm sure you know, there is a LOT of interaction between these devices. The only way I was even to get the green centered was between rotating the G90 yoke and fiddling with the CPC flare ring.

Unfortunately, I have no more time to spend on this for a few days. I am going wild boar hunting tomorrow and won't be back online until Sunday. The wife is none-too-happy leaving her with an unwatchable projector!

Steve

[andreas]

WOW! Nice pictures! I will folow your documentation with interest. I guess you swap green and blue if thats the case. I found out that part with interaction to but i dont realy understand it yet. Weard that the yokes afect eachother.

[mr_ro_co]

[Nashou66]

Steve, For the placement of the coils relative to direction. I was looking at how the Marquee Coils are arranged back when I was experimenting myself. The static is placed first in the coils then the Dynamic. Same for the Barco coils, they are placed in the front. Now for the Barco coils they did something different regarding the magnets, for the green yoke they have them flipped 180 degrees. So the polarity for the Red and Blue are the same and green is opposite. I beth they did this to counter the magnetic field interaction that may occur between the tubes, but I think they are placed a bit closer to each other than in a Marquee. Not sure tho .

Ok back to the Coils, my theory is to have the Static first and dynamic second because the overall beam will get focused first by the static then the dynamic will finish off the edge focus after the dynamic has completed the overall focus. I pointed this theory out in the franken Yoke thread somewhere. There is a lot of info in that thread so finding it would be daunting .

Nashou

[mr_ro_co]

[mr_ro_co]

Athanasios,

I found a small neodymium magnet and using it on a piece of tape and also by placing the G90 yokes year each other, all three yokes seem to have identical magnetic field orientation. So they do not appear to be using the same approach as the Barco yokes with one flipped relative to the other two.

If the G90 yokes are situated with the same magnetic polarity as the Thomson yokes, the static coil is last (the way I have been using them).

I don't know the layout of the coils in the Thomson yokes. Do you? I guess I can experiment some more before skipping town for a few days.

Steve

[Nashou66]

The static is before the dynamic in the thompson yolks. From what I remember dismantling one.

Athanasios

[mr_ro_co]

Based on concerns of the internal bobbins rotating undesirably when the whole yoke is rotated about the neck, which is what unfortunately happens if you shim them enough to get a wobble free fit, I put the yokes back in their original plastic housings and tried reinstalling them. They take up too much space now: The CPCs won't fit in the last space on the neck between the neckboard cage and the focus yoke. Does this mean successful installations also did not use the plastic housings, as I originally intended, or were the CPC magnets then omitted? Without hacking up the plastic housings, I can't see how everything can fit using them. The G90 uses electronically controlled CPCs that take up more room than the passive ones, so that must mean the G90 uses a much shorter deflection yoke than the Marquee.

Steve

[mr_ro_co]