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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Thu Apr 11, 2019 11:51 am Post subject: Green focus on Barco 1209s |
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Dear Members,
Mechanical adjusting the focus on my pj I noticed a strange thing.
With midpoint focus on 57 and contrast to 80 when I move everything I cannot obtain a good focus on green tube.
1- Center focus
2- Corner focus
3- Scheimpflug
Then I checked the 2pole/4pole rings and the defocused lines and dots are centered/round.
Now the strange thing:
The deflection block is fully against the CRT bulb (correct)
The focus unit is not 8-10mm apart from it (as shoud be and actually is on the R e B tubes) but is fully against the deflection block. To increase the center focus I shoud go even further.
Is there an electronic focus pot for the green tube that shoud be unadjusted on some board?
Thanks for any advice,
Alberto
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gjaky
Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary
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Link Posted: Fri Apr 12, 2019 6:29 am Post subject: |
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Does the electronic focus work at all on green?
Does the green tube has the exact same part number as the other two tubes?
_________________ projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Fri Apr 12, 2019 8:50 am Post subject: |
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Hi, thanks for your answer.
The electonic focus is working, with that I can achieve perfect focus all round (with some settings at the end of the scale anyway).
But I would understand what's going wrong with the setup.
The 3 tubes are standard Barco.
Regards,
Alberto
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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Sun Jun 14, 2020 8:00 am Post subject: |
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Hi members!
I refresh this old thread because after a new check I found that the tubes, even if Barco labelled, are all different.
R - P19LPB03RJA
G - PT22-30
B - P19LUG03MB
On R and B perfect focus but problem with G.
I have perfect midpoint focus with focus unit very close to the deflection unit, but side focus is very poor.
Where should be the issue?
Thanks,
Alberto
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24303 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Sun Jun 14, 2020 2:27 pm Post subject: |
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If the focus on the face of the tube is perfect, then you may have the wrong lens on the set, if it's designed for curved screens, or the C element has the wrong curve on it.
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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Sun Jun 14, 2020 2:39 pm Post subject: |
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Hi Curt!
No, the focus on the face of the tube is not perfect, it reflects that on the screen!
The 3 lenses are HD-120
Thanks!
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24303 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Mon Jun 15, 2020 1:48 am Post subject: |
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OK, swap the focus yoke wiring between tubes to see if the problem follows the focus board channel, or if the problem stays on the same tube. If it switches, the focus board is bad, which is the H shift board.
If it stays with the same tube, then the focus yoke is bad (swap that between tubes to confirm), or there may be a problem in the tube (you could switch tubes to confirm that as well).
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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Mon Jun 15, 2020 11:12 am Post subject: |
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Hi, already swapped the focus yoke wiring but nothing change.
The PJ is ceiling mounted so is not so easy remove the tubes.
Is it possible swap the yokes between tubes without remove them?
Anyway I noticed another thing that let me suspect that the tube is good.
At 15.7 Khz internal pattern the focus is correct.
More the resolution grow and more the sides are defocused (especially the left bottom corner).
Let me know if the last thing could have any importance.
Thanks!
Alberto
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gjaky
Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary
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Link Posted: Mon Jun 15, 2020 11:34 am Post subject: |
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I seem to remember that here were threads mentioning that some of the PT22 tubes have a shorter neck than LCP/LUG tubes and they need a different focus coil... please make a search on this here.
_________________ projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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alb_qwerti
Joined: 30 Sep 2008 Posts: 41 Location: Italy
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Link Posted: Tue Jun 16, 2020 12:20 pm Post subject: |
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Hi Jaky,
I found that old post!
Very interesting but my green tube is PT22-30 and has the same dimensions of the others.
Anyway, to swap the focus yokes you need to remove the tubes?
Should worth a try to swap the neck boards first that is easier?
Thanks,
Alberto
[img]file:///C:/Temp/WP_20200616_13_52_35_Pro.jpg[/img]
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