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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Tue Sep 30, 2008 4:26 am Post subject: XG-750 Green Tube Won't Focus ((Desperate to Solve)) |
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Hey all, I've been enjoying my new CRT but I have two questions about further refining my setup::
My green tube wont focus on the left and right sides, and top and bottom to a lesser extent. The left side is the worst of all. The other two tubes are fine and the issue is not with the lenses, I can see it defocused on the tube face. I have already tried the focus pot and that only helps with the center. Is there anything I can do to get the edges focused?
Other question was what benefit g2 calibration has, it looks quite complex and needs test patterns I don't have. What would I gain from this? I noticed the last step says to make sure the test and normal position of the akb switch make little difference in the image, and that is already the case right now for me. I don't know if that means a calibration is unnecessary. Could someone post a before and after of g2?
Last edited by Satanier on Fri Jan 09, 2009 3:43 am; edited 2 times in total
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Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
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| Posted: Tue Sep 30, 2008 10:10 am Post subject: Re: Two Small Questions (XG-75) |
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| Satanier wrote: |
Other question was what benefit g2 calibration has, it looks quite complex and needs test patterns I don't have. What would I gain from this? I noticed the last step says to make sure the test and normal position of the akb switch make little difference in the image, and that is already the case right now for me. I don't know if that means a calibration is unnecessary. Could someone post a before and after of g2? |
Proper G2 *can* make a difference that is beneficial and noticeable, but more importantly, NOT doing the G2 procedure correctly can REALLY make your picture terrible, unwatchable in fact.
Before you go into that arena, ask yourself if you feel capable with living with the results EVEN IF THEY ARE TERRIBLE.
Also, perhaps reflect on the possibility that it may not make a dramatic improvement and it will be a LOT of effort. The instructions need to be followed VERY VERY closely.
Before you attempted G2, I would recommend buying a colorimeter to check your greyscale. Then attempt to set your greyscale using the "user" level controls available to you, and only if that didn't work would I recommend *maybe* doing the electronic G2 setup procedure.
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emdawgz1
Joined: 14 Mar 2006
Posts: 7949
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| Posted: Tue Sep 30, 2008 12:39 pm Post subject: |
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I would be really really really hesitant before i adjusted G2 on my nec.
I would exhaust other user adjustments, including greyscale w/ a proper color meter.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Tue Sep 30, 2008 2:18 pm Post subject: |
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Your NEC has a bad focus board. I've seen this a lot. I have spares, or can repair yours. Email me at curtpalme@shaw.ca.
Cheers!
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dropzone7
Joined: 12 Jun 2007
Posts: 1069
Location: Charlotte, NC
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| Posted: Tue Sep 30, 2008 3:54 pm Post subject: |
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I would get your focus issues ironed out before attempting any other adjustments. Changing a board is an easy fix and Curt can turn these around pretty quick in my experience.
Now, regarding the G2 adjustment. This was one of the scariest things ever if you read all the disclaimers, warnings and explanations of users here. I personally found the procedure to be fairly easy. It is time consuming and very iterative as are most video adjustments but trust me, if I can do this then anyone can. I did see a visual improvement right away and this laid the framework for later adjustments in grayscale using a colorimeter. If you have a digital voltmeter and know how to use it then just print out the procedure, study it over and over. Let your projector warm up properly before beginning and be patient.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Sat Oct 11, 2008 2:10 am Post subject: |
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What would happen if I swapped the focus wire from my green tube onto my blue, since the blue is supposed to be defocused anyway? I just can't afford to have the board repaired at this point in my life.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Fri Oct 17, 2008 8:51 pm Post subject: |
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Bump, anyone? ^^^^
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Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
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| Posted: Fri Oct 17, 2008 8:58 pm Post subject: |
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If you swap all the control wired for focus from green to blue, then, if the problem is with the green channel focus control, the problem will move to the blue tube. This won't cause any problem, and is a common troubleshooting technique. If the problem stays with the tube, it tells you its a problem inherent with the tube, or the actual controls installed ON the tube(ie. the focus yoke, astig magnets, etc...).
You can run with the blue/green focus controls swapped without issue, of course.
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Sat Oct 18, 2008 3:29 am Post subject: |
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| emdawgz1 wrote: | I would be really really really hesitant before i adjusted G2 on my nec.
I would exhaust other user adjustments, including greyscale w/ a proper color meter. |
You can't fix an incorrectly set up G2 on an XG by playing with greyscale. You have to get G2 correct first. It's fundemental. Everything else builds on it.
Kal
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Sat Oct 18, 2008 8:31 am Post subject: |
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Why did G2 come up at all?
99% of NECs just need a little Kelvin adjustment.
Get the F Drive fixed and leave G2 alone.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Sat Oct 18, 2008 10:20 pm Post subject: |
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| Mark_A_W wrote: | Why did G2 come up at all?
99% of NECs just need a little Kelvin adjustment.
Get the F Drive fixed and leave G2 alone. |
I can't afford to have F drive fixed right now, so I'm going to swap the blue and green focus wires, since blue is defocused anyway. What sort of kelvin adjustment do you recommend? Although a custom gamma curve on HTPC has mostly solved the brightness issue if a kelvin could make it even better I would want to try.
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Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
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| Posted: Sat Oct 18, 2008 11:03 pm Post subject: |
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Without a colorimeter, you will be pretty much wasting your time doing any "Kelvin" adjustments.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Mon Oct 20, 2008 3:00 am Post subject: |
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Well I swapped the focus connector from the blue and green tubes, and the problem remained on the green, ideas?
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Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
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| Posted: Mon Oct 20, 2008 3:04 am Post subject: |
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I have posted my ideas several times yet you have assured me it is not optical, nor setup related, but I'd still bet it is. Tube problems which result in what you describe are very unusual, BUT, poor, sloppy physical placement and bad optical setup is commonplace...
If the problem remains when you swap control, it is EITHER the components ON the tube which IMPLEMENT the control, or the tube itself.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Mon Oct 20, 2008 3:43 am Post subject: |
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| Elaine Benes wrote: | I have posted my ideas several times yet you have assured me it is not optical, nor setup related, but I'd still bet it is. Tube problems which result in what you describe are very unusual, BUT, poor, sloppy physical placement and bad optical setup is commonplace...
If the problem remains when you swap control, it is EITHER the components ON the tube which IMPLEMENT the control, or the tube itself. |
Well I can see the blurriness on the tube face looking through the lens, so I would say the issue is not optical.
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Wed Oct 22, 2008 5:54 pm Post subject: |
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Bump, issue is electronic...
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Sat Nov 01, 2008 6:35 pm Post subject: |
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Bump, I swapped the focus board cable on blue and green tubes and the problem persisted on green. (uneven focus some zones not focusing at all on green, issue is electronic)
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Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
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| Posted: Sat Nov 01, 2008 7:12 pm Post subject: |
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Use your critical thinking faculties.
You were given advice to look at "focus balance" in the electronic controls at one point, did you do that ?
Have you nulled all electronic focus controls and astig controls and started from scratch(working from the middle out, of course...)?
With the focus controls switched between green and blue, does the green focus control affect the blue tube as you would expect it to ?
When all focus and astig controls are nulled, is there any change to the focus pattern ?
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sat Nov 01, 2008 8:45 pm Post subject: |
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Your astig board or astig adjustments could be bad too. What do your astig dots look like?
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Satanier
Joined: 25 Aug 2008
Posts: 185
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| Posted: Sat Nov 01, 2008 10:08 pm Post subject: |
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| Elaine Benes wrote: | Use your critical thinking faculties.
You were given advice to look at "focus balance" in the electronic controls at one point, did you do that ?
Have you nulled all electronic focus controls and astig controls and started from scratch(working from the middle out, of course...)?
With the focus controls switched between green and blue, does the green focus control affect the blue tube as you would expect it to ?
When all focus and astig controls are nulled, is there any change to the focus pattern ? |
I tried all those things yes, it doesn't seem to be anything obvious. It wont go anywhere near focused.
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