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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Apr 25, 2011 2:28 pm Post subject: |
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Oh, by the way......YES....... Seriously? 
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun May 01, 2011 5:14 pm Post subject: G90 focus yokes undressed and violated |
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Gentlemen,
I took apart one of my G90 focus yokes, documented the position of all the coils and measured them.
Scott, Athanasios, Chris, Andres: Can you please identify which coils are for which purpose?
Also, please clarify what you mean by "rotate" the magnet(s).
Best regards,
Steve
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Mon May 02, 2011 2:44 pm Post subject: |
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Running precision impedance sweeps on the G90 focus yoke coils from 10Hz to 100KHz from an 8 bit ISA analyzer card in a PC running DOS 6.22.
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Tue May 03, 2011 12:45 am Post subject: |
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The blu/red wired coil (red tape) should be the dynamic focus winding.
gry/brn and orn/wht, most likely the six pole dynamic stig windings.
yel/grn and blu/red, four pole dynamic stig windings.
orn/wht (yel/grn) would be the static focus winding.
The inductance values were taken with the magnet structure assembled around the bobbins as they are used? I think so.
Very important to reassemble the magnet pieces in the same order and orientation as original. The CRT can be damaged if not.
The inductance values are pretty close to Marquee values except the static focus winding is lower, IIRC.
You can drive the stig windings with a DC current to adjust beam shape over the whole screen. Different areas of the screen need different correction so DC current is really only useful for center correction.
Scott
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Tue May 03, 2011 4:56 am Post subject: |
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| tse wrote: | The blu/red wired coil (red tape) should be the dynamic focus winding.
gry/brn and orn/wht, most likely the six pole dynamic stig windings.
yel/grn and blu/red, four pole dynamic stig windings.
orn/wht (yel/grn) would be the static focus winding.
The inductance values were taken with the magnet structure assembled around the bobbins as they are used? I think so. |
Correct.
| tse wrote: | | Very important to reassemble the magnet pieces in the same order and orientation as original. The CRT can be damaged if not. |
Understood. Yes, I was very careful to put it back together exactly as it was. Sony put some marks on the magnets that helped with this.
| tse wrote: | The inductance values are pretty close to Marquee values except the static focus winding is lower, IIRC.
You can drive the stig windings with a DC current to adjust beam shape over the whole screen. Different areas of the screen need different correction so DC current is really only useful for center correction.
Scott |
Did you mean "can't" drive the stig windings with DC?
Thanks!
Steve
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Tue May 03, 2011 10:48 pm Post subject: |
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You can drive the stig windings with DC. The coil will then have the same effect as the little permanent magnet neck magnets. The same "correction" over all parts of the screen. It is fun to play with and will give one a good idea what signal would be required to do dynamic, full screen correction. Currents will be in the 0.1A, or so, range.
Sony dynamic winding = 41uH
Marquee = 31uH
Might be close enough to work.
Sony static = 1.59mH
Marquee = 33mH
This might be a problem. If the gauss of the permanent magnet is very close to correct without static focus current then maybe ok in the center. The top and bottom dynamic focus is also applied to this winding. There might not be enough range for good top and bottom modulation. The magnetic strength added to (or subtracted from) the permanent magnet is determined by 1/2 x L x I^2. The Sony coil at 1.59mH will need alot more current than the Marquee coil at 33mH to produce the same magnetic strength.
Sony stig = 57uH
Marquee stig = 147 or 159uH
Might work but the Sony winding will need more current to do the same thing as the Marquee for the same reason as the static winding.
There are efficiency factors to take into account (I have no idea what they are) but I do believe the Sony type coils are somewhat more efficient so things may not be as far off as they look.
Scott
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Wed May 04, 2011 10:19 am Post subject: |
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Would anyone be able to help with the pinouts for Barco 808s focus yokes and 909 focus yokes. I have an 808 and 909 manual but they does not contain this information.
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Wed May 04, 2011 1:15 pm Post subject: |
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| tse wrote: | You can drive the stig windings with DC. The coil will then have the same effect as the little permanent magnet neck magnets. The same "correction" over all parts of the screen. It is fun to play with and will give one a good idea what signal would be required to do dynamic, full screen correction. Currents will be in the 0.1A, or so, range.
Sony dynamic winding = 41uH
Marquee = 31uH
Might be close enough to work.
Sony static = 1.59mH
Marquee = 33mH
This might be a problem. If the gauss of the permanent magnet is very close to correct without static focus current then maybe ok in the center. The top and bottom dynamic focus is also applied to this winding. There might not be enough range for good top and bottom modulation. The magnetic strength added to (or subtracted from) the permanent magnet is determined by 1/2 x L x I^2. The Sony coil at 1.59mH will need alot more current than the Marquee coil at 33mH to produce the same magnetic strength.
Sony stig = 57uH
Marquee stig = 147 or 159uH
Might work but the Sony winding will need more current to do the same thing as the Marquee for the same reason as the static winding.
There are efficiency factors to take into account (I have no idea what they are) but I do believe the Sony type coils are somewhat more efficient so things may not be as far off as they look.
Scott |
Scott,
That's a huge difference on the static winding. I'll have to confirm my measurements and I'll measure one of the Tompsons to see what I get for its static winding. I took a plot of the impedance of all the windings from 10Hz to 100KHz with an audio analyzer, which is more than enough to get the DCR and then a good chunk of the slope of the impedance based on the inductance value, but I may have made a mistake.
Unfortunately, I don't have time to do this until next week. I will be out of town on vacation until Sunday evening. I will revisit this when I get back.
Thanks for your help!
Steve
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Thu May 05, 2011 6:03 pm Post subject: |
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It might be worthwhile rechecking the static winding inductance. The 70 ohms of resistance sounds like a lot of turns of small gauge wire which should be high inductance.
Scott
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Thu May 05, 2011 6:04 pm Post subject: |
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It might be worthwhile rechecking the static winding inductance. The 70 ohms of resistance sounds like a lot of turns of small gauge wire which should be high inductance.
Scott
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun Sep 18, 2011 4:46 pm Post subject: |
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| tse wrote: | It might be worthwhile rechecking the static winding inductance. The 70 ohms of resistance sounds like a lot of turns of small gauge wire which should be high inductance.
Scott |
Scott,
I'm finally able to revisit this task. Just been too busy lately to give this hobby as much time as I'd like.
I found a shop that has a Sencore that can do a precision inductance measurement. I'm going to take one of the G90 yokes and one of the Thompson yokes and have them measure both.
Do you have the pin-out for the coils (static, dynamic, stig, etc.) for the Marquee/Thompson? I'm determined to do this in the next day or so.
Best regards,
Steve
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Sun Sep 18, 2011 5:17 pm Post subject: |
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orn/yel = dynamic winding (< 1.0 ohm)
blk/red = static winding (about 40 ohms)
brn/grn = thermistor for temperature sensing (about 20k ohms)
Scott
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun Sep 18, 2011 7:01 pm Post subject: |
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| tse wrote: | orn/yel = dynamic winding (< 1.0 ohm)
blk/red = static winding (about 40 ohms)
brn/grn = thermistor for temperature sensing (about 20k ohms)
Scott |
Excellent - thanks!! Those are DCR values for the coils? What coil(s) does the stock dynamic astig function on the Ultra use?
Steve
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Sun Sep 18, 2011 7:30 pm Post subject: |
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mr roco, is it your intention to use g90 yokes?
what i want to know is if the bg808s yokes are the same as the 909 yokes.
these could be rewound to match marquee inductance values of course, but what is the biggest diameter one could use.
909 yokes are still hard to find hence the question about 808 yokes.
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun Sep 18, 2011 8:15 pm Post subject: |
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| dvh99 wrote: | mr roco, is it your intention to use g90 yokes?
what i want to know is if the bg808s yokes are the same as the 909 yokes.
these could be rewound to match marquee inductance values of course, but what is the biggest diameter one could use.
909 yokes are still hard to find hence the question about 808 yokes. |
Correct.
Steve
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Sun Sep 18, 2011 11:32 pm Post subject: |
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| mr_ro_co wrote: | | tse wrote: | orn/yel = dynamic winding (< 1.0 ohm)
blk/red = static winding (about 40 ohms)
brn/grn = thermistor for temperature sensing (about 20k ohms)
Scott |
Excellent - thanks!! Those are DCR values for the coils? What coil(s) does the stock dynamic astig function on the Ultra use?
Steve |
Yes, that is DCR. There is a seperate four pin connector for the stig windings. There are two four pole windings. One is in an "X" configuration, the other in a "+". Their DCR is around one ohm.
Scott
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Mon Sep 19, 2011 1:39 pm Post subject: |
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| tse wrote: | | mr_ro_co wrote: | | tse wrote: | orn/yel = dynamic winding (< 1.0 ohm)
blk/red = static winding (about 40 ohms)
brn/grn = thermistor for temperature sensing (about 20k ohms)
Scott |
Excellent - thanks!! Those are DCR values for the coils? What coil(s) does the stock dynamic astig function on the Ultra use?
Steve |
Yes, that is DCR. There is a seperate four pin connector for the stig windings. There are two four pole windings. One is in an "X" configuration, the other in a "+". Their DCR is around one ohm.
Scott |
Okay, understood.
Steve
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun Sep 25, 2011 1:35 am Post subject: |
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Okay, finally got a chance to put the Sencore on these yokes to get precise inductance measurements of all the coils. Strangely enough, my audio analyzer was really close on the values for the dynamic and stig coils, but was totally wrong on the static focus coil. The Sencore measured 43 mH for the Sony static focus coil, much closer to the 33 mH value for the Marquee's, which makes sense given the 70 ohms of DCR for the Sony coil, as Scott pointed out.
Scott, please review my drawing. I labeled the coils based on your earlier replies and updated the inductance values with the Sencore measured ones.
Do you think all these coils could be connected as-is to the same purpose connections on the Marquee, or do the stig coils need to be rewound? I'd actually be willing to do that, if you think it's needed. And de-wind the static and dynamic windings, if also needed.
One step closer to getting these put in my hot-rodded MP9!
Thanks!
Steve
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dvh99
Joined: 25 Dec 2009
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Location: nederland
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| Posted: Sun Sep 25, 2011 4:25 pm Post subject: |
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how is the 6 pole stig going to work in the marquee?
don`t you need an extra stig amp for that?
the 6 pole is for final shaping of the electron beam, does this connection need a lower voltage applied to it?
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mr_ro_co
Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM
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| Posted: Sun Sep 25, 2011 6:35 pm Post subject: |
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Scott,
I measured the DCR on the Thompsen yoke coils, and based on the inductance values you've provided in the past, created a drawing that should be the definitive "apples to apples" comparison between the Marquee and the G90 focus yokes. Please review for correctness. The dynamic stig coils for the Marquee are over 6 ohms DCR, and I assumed the smaller value of the two would obviously go with the lower inductance value of the two values you've given in the past for these coils. The DCR for the Marquee's static coil and dynamic coil are otherwise exactly what you said.
So the question that should be raised by this comparison is: Is the Marquee going to have a problem driving the G90's 4-pole dynamic stig windings?
Best,
Steve
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