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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Feb 26, 2013 9:46 am Post subject: How sharp is a NEC 9PG plain? |
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I have totally recapped my boss' NEC 9PG plain, that was suffered from the dreaded no video issue, the unit is working since then, but honestly I am not pleased with the picture quality at all. This is the first PG plain that I see actually working so I can't decide if it is reached it's capabilities. I can't make scanlines visible at all even at 1024x768, not to mention 720P. movies look good though, but windows desktop looks like crap. On my PG xtra with careful setup I can see scanlines at 720p or 1280x1024 from close, at 1024x768 the scanlines are screaming and I also have HD-6 lenses on the xtra. I've tried the astig rings so far and it was already adjusted to the tightest beam size, electronic focus seems to work, and all colors have about the same sharpness, just not sharp enough. The machine has less than 1000hrs in it, pristine tubes, lighting up a 85" wide screen, contrast at 75 brightness at 55.
Is the PG plain that much worse than my PG xtra, or it really should perform better?
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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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Zolzar
Joined: 26 Jun 2009
Posts: 252
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| Posted: Tue Feb 26, 2013 2:01 pm Post subject: |
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I'd think you should be able to see scan lines at 720p. I can with my 10PG and its absolutely distracting. The scan lines are there on my setup with 1080i but only noticeable at about 2 meters from the screen. I would think you should be seeing scan lines.
John
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Tue Feb 26, 2013 5:31 pm Post subject: |
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Yep, work on focus and astig setup. Unless the tubes are real soft and worn, you should absolutely be able to see the scan lines.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Feb 26, 2013 5:44 pm Post subject: |
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Ok that's what I thought, actually there is a spare focus board, but the machine is on a high ceiling, so I thought I ask before do hard work. 
_________________
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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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Tue Feb 26, 2013 6:11 pm Post subject: |
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It should be sharper than any ES focusing set (save for brand new tubes maybe), but not as sharp as an 8" EM focusing set. Usually if the focus board in the PG is bad, either you'll get an error code on the back, or the sides of the image will be way out of focus. Astig is really important as Tinman says. One smalll bump of hte astig magnets on the tubes, and your focus/astig ends up being a mile off.
Or wait, in your case, a Km off. 
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Mar 05, 2013 3:48 am Post subject: |
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Not quite as sharp as a good XTRA, but not far off. Can be tricky to get the astig just right sometimes and im not sure why.
Did you bleed the tubes?
Itll be about 1.6klms off Curt 
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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 Mar 05, 2013 3:57 am Post subject: |
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Oh get picky...1.62! 
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Mar 05, 2013 4:09 am Post subject: |
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I aint partin' hairs over 20 meters!!! 
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Tue Mar 05, 2013 4:36 am Post subject: |
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| CasetheCorvetteman wrote: | | I aint partin' hairs over 20 meters!!! |
You mean 65.62 feet
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Mar 05, 2013 12:20 pm Post subject: |
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| CasetheCorvetteman wrote: | Not quite as sharp as a good XTRA, but not far off. Can be tricky to get the astig just right sometimes and im not sure why.
Did you bleed the tubes?
Itll be about 1.6klms off Curt |
The tubes are not bleeded, but honestly I am not worried about that. The owner wanted to repair it fast...
Do you have a guide how to set the astig? I read Guy Kuo's guide, I achieved a good astig (symmetrical round dots) but the overall sharpness is unstatisfactory, the focus yokes are similarly aligned as it is in his parts machine.
_________________
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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hansilili
Joined: 09 Mar 2007
Posts: 302
Location: Köln, Germany
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| Posted: Tue Mar 05, 2013 2:34 pm Post subject: |
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With my 10PGplus i have the feeling, that resolution is a bit softer that with the xtra. But the xtra made only half the screen size on a smooth screen material (draper Baronet) whereas the 10PGplus fires a 3,60 m wide Phifer sheerweave so blooming and screen structure needs to be considered too.
Cheers
hansilili
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Tue Mar 05, 2013 3:54 pm Post subject: |
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| gjaky wrote: | | CasetheCorvetteman wrote: | Not quite as sharp as a good XTRA, but not far off. Can be tricky to get the astig just right sometimes and im not sure why.
Did you bleed the tubes?
Itll be about 1.6klms off Curt |
The tubes are not bleeded, but honestly I am not worried about that. |
You should be! The pressure inside the cooling chamber can get high enough to shatter the glass. We've seen this often enough now to worry about it. Bleeding is cheap insurance.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Mar 05, 2013 4:06 pm Post subject: |
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| Tinman wrote: | | gjaky wrote: | | CasetheCorvetteman wrote: | Not quite as sharp as a good XTRA, but not far off. Can be tricky to get the astig just right sometimes and im not sure why.
Did you bleed the tubes?
Itll be about 1.6klms off Curt |
The tubes are not bleeded, but honestly I am not worried about that. |
You should be! The pressure inside the cooling chamber can get high enough to shatter the glass. We've seen this often enough now to worry about it. Bleeding is cheap insurance. |
Yeah, I know, but it is a very time consuming procedure and usually I have to do 'more important' things than tinker his projector, I think I've suggested to bleed the tubes, but it sank into oblivion. Anyway once I bleed my PG xtra's tubes, the blue tube shot out the screw, the red was moderate, but the green was at so low pressure that I couldn't even add a buble to it.
_________________
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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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Mar 06, 2013 12:27 am Post subject: |
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Well stop using it til you DO have time. Dont waste perfectly good tubes.
And dont waste time doing astig on tubes that will be coming out for bleeding.
Its a 1 hour job max. Dont turn it on again til its done.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Mar 06, 2013 12:28 am Post subject: |
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| AnalogRocks wrote: | | CasetheCorvetteman wrote: | | I aint partin' hairs over 20 meters!!! |
You mean 65.62 feet |
Whats that in barley corns? ( im not making that up!! )
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hansilili
Joined: 09 Mar 2007
Posts: 302
Location: Köln, Germany
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| Posted: Wed Mar 06, 2013 8:05 am Post subject: |
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Not sure if the bleeding advice is not overrated. Did it myself on a Sony 1252 and twice on two differnt NEC xtras (hurt my eye only once). Guess what, after a year of frequent use the bubbles were gone and the gylcol chambers had the same pressure again.
If the cracking glass is really related to hydrophilic glycol building up pressure due to expansion of a non compressable liquid, then I don't think that the issue could have been prevented by letting in a small air buble only once.
TEll me, who of you has yet obeserved, the procedure of bleeding where previously was no bubble resulted in the gas bubble being of stable size for a year?
BEst regards
hansilili
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Wed Mar 06, 2013 12:29 pm Post subject: |
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| CasetheCorvetteman wrote: | | AnalogRocks wrote: | | CasetheCorvetteman wrote: | | I aint partin' hairs over 20 meters!!! |
You mean 65.62 feet |
Whats that in barley corns? ( im not making that up!! ) |
2353.06 Barleycorns or 43.75 Cubits
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Mar 07, 2013 12:01 am Post subject: |
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| hansilili wrote: | Not sure if the bleeding advice is not overrated. Did it myself on a Sony 1252 and twice on two differnt NEC xtras (hurt my eye only once). Guess what, after a year of frequent use the bubbles were gone and the gylcol chambers had the same pressure again.
If the cracking glass is really related to hydrophilic glycol building up pressure due to expansion of a non compressable liquid, then I don't think that the issue could have been prevented by letting in a small air buble only once.
TEll me, who of you has yet obeserved, the procedure of bleeding where previously was no bubble resulted in the gas bubble being of stable size for a year?
BEst regards
hansilili |
Me. On a number of NECs now. All mine still have bubbles. Its not over rated, go up and read what Tinman said, its been seen here a heap of times.
You can take the chance if you like, but for the sake of a simple job, why would you risk it?
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