CurtPalme.com Home Theater Forum

[cmjohnson]

I'd just like to mention this:


As of this time, the types of focus yokes that have been evaluated for Marquee usage are relatively few. They do NOT include such rarities
as the Sony G90 yokes, which MAY or MAY NOT be suitable for use in a Marquee. Even if they are suitable, it is likely that they will need
to be modified.

I would advise against anyone going out and buying any random type of focus yokes in the hopes that they'll get incredible razor sharp
focus out of them in their "as is" condition when installed in a Marquee, unless you're willing to invest time and effort into modifying them
yourself. Which will require a not insignificant level of technical knowledge.

The number and type of yokes that are known to represent an improvement over the stock Thompson yokes in a Marquee are, at this
time, few and limited, and every one of them needs SOME level of adaptation to work. At the very minimum, wiring harnesses need
to be changed out and both electrical and magnetic polarity need to be evaluated and reoriented as required. Most types are out of
spec with regard to magnetic and/or inductance values.

Right now the Barco 2302 (3203? I forget...) yokes are looking like the best stock variety to use. But even they aren't optimal.

Eventually, either Athan or myself will probably evaluate every focus yoke assembly we can get our hands on, including the G90 yokes,
but at the moment, be aware that no yokes you can get are optimized if they haven't been modified for this purpose.


CJ

[Nashou66]

Great points Chris, I know of only one person who used the G90 yoke and that was Antorsea(Andre) in Spain. He said they work but are much larger since they have not only astig windings but also electronically controlled CPC magnet windings. Those would be rendered useless in a marquee unless you devise a separate board with amps and trimpots to adjust them.

I got a PM from Mike Parker about the 909 coils, he will try to get them out when he can, I am in no hurry as I still have other things on my plate.

I also got a 100ft roll of 18 gauge wire, the 16 gauge is just to hard to work with although it worked in the Ampro structure I got from TSE that had no Dynamic winding.

Athanasios

[pezzettino]

[Nashou66]

Atorsea in Spain is the one who used the G90 yokes but sold them for the 1292's which he said worked better.

But let us know how they work, there will be extra pins on your connector that would be the CPC magnets, those will not be used. you'll have to ask him. I'll look for a thread on AVS where he explained how they work.

Athanasios

[pezzettino]

Many, many thanks Athanasios.

Let me know


Vincenzo

[Nashou66]

Well i found this post, it has my efforts from the Barco coils too. some of Andre's pics are missing.

http://www.avsforum.com/avs-vb/showthread.php?t=885734&highlight=frankenyokes

And this thread, where Andre comments on the two types:

http://www.avsforum.com/avs-vb/showthread.php?t=1035912&highlight=frankenyoke+g90

Athanasios

[pezzettino]

Sorry Atha but the two link are the same.

[Nashou66]

[pezzettino]

Thanks Nashou.

Sorry

Vincenzo

[Sparky015]

Hey guys, found some Sony 1-452-810-11 coils on the bay. These aren't the 811-11s mentioned. Just wondering if these are also the coils with astig?

Paul

[Nashou66]

Paul, those coils will not work, IIRC they are G70 coils and the hole is too narrow.

Edit, just found them, those are the convergence coils for the 1292. Not the Focus colis.

Athanasios

[Sparky015]

I thought the harness looked small! Thanks for checking that for me, Athanasios

[Nashou66]

No problem, I wish the pics earlier in this thread would be removed or shrunk.

Athanasios

[AnalogRocks]

[AnalogRocks]

[Nashou66]

[AnalogRocks]

[AnalogRocks]

[cmjohnson]

Time for some updates. There's a newer topic or two on Frankenyokes and also on the G90 focus yokes.

I've acquired a set of G90 focus yokes as well and have done some evaluation on them. They have potential to be the best yokes yet
for a Marquee, owing to their long field design. It seems fairly evident that the longer their magnetic fields are around the CRT necks, the more control a given yoke design has over the beam shape.


Plans are moving along to establish a procedured to optimize most any focus yoke for a Marquee. It will involve both rewinding of dynamic and static focus coils to optimal inductance values and also adjustment of the strength of the permanent magnets in the coils to the optimal value range. Equipment is being built to facilitate those changes.



CJ

[cmjohnson]

Here's an update for those of you who are following this project:


I have found that the yokes made for Barco Cine 8 (and maybe Cine 9...probably) projectors are
a very good choice for use in a Marquee. You simply have to adapt the wiring harness to work.

The yoke in question is the KF-3203 and may bear the Barco part number label of 4000025.


The CRTs are sharply focused with these coils installed and not even plugged in.

I say that again: The CRTs are sharply focused with the coils installed and NOT EVEN PLUGGED IN.



The coils are still the wrong value but they can be rewound to the proper values.




CJ

[Nashou66]

Just to clarify, the barco coils had to be rewound correct?

Athanasios

[cmjohnson]

Content retracted due to bad data....will report back after making corrections.


The static focus is still right with these. It makes them good candidates for rewinding to proper specs.