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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Sun Nov 30, 2008 10:29 pm Post subject: Decreasing brightness on NEC 6PG (SELECO SDT-200) Pictures ! |
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Hello,
My NEC 6PG ( Seleco SDT-200 exactly) Has a strange trouble. Anyone know ?
I put the power on. Menus OK, but when I switch on picture or pattern white, brightness suddenly decrease. Projector always run but picture is near invisible. A lot wrong capacitors were changed on boards with all trims with no results.
A friend of mine can give me a PG+ power supply to make a test. PG and PG+ are compatibles ?
Thanks for help.
Last edited by Choukard on Tue Dec 02, 2008 9:28 pm; edited 1 time in total
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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: Mon Dec 01, 2008 4:17 am Post subject: |
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NEc made sets for Seleco? Pictures please, that's a new one on me.
I'd suspect a video problem, not a power supply issue.
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Brooklyn
Joined: 17 Sep 2007
Posts: 494
Location: Morgan Hill, CA
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| Posted: Mon Dec 01, 2008 7:36 am Post subject: |
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"A lot wrong capacitors were changed on boards with all trims with no results"
What does that mean?
If this is a Nec, don't ever touch any of the many trim pots on the video board on the rear of the projector. What resolution(s) are you inputing?
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Mon Dec 01, 2008 9:41 am Post subject: |
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| Curt Palme wrote: | NEc made sets for Seleco? Pictures please, that's a new one on me.
I'd suspect a video problem, not a power supply issue. |
OK Curt, I'll make pictures for you.
After a new test, picture stay OK for 15 minutes. Decrease after. What's board would be defect ?
I only have a 6PG+ to interchange some board, but can I do something with it ?
Thanks.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Mon Dec 01, 2008 9:45 am Post subject: |
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| Brooklyn wrote: | "A lot wrong capacitors were changed on boards with all trims with no results"
What does that mean?
If this is a Nec, don't ever touch any of the many trim pots on the video board on the rear of the projector. What resolution(s) are you inputing? |
You can see brown traces on board, from capacitors. I never touch trims. Only replacing wrong cpacitors. It's for use with line doubler. But that's not the problem. Trouble is here with no input. You only put a pattern test with with windows and brightness/contrast decrease quickly to a very dark picture, near invisible.
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1031
Joined: 22 Mar 2006
Posts: 657
Location: Finland
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Dec 01, 2008 3:12 pm Post subject: |
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Since I'm not exactly sure what projector you have, I'll shoot from the hip here. As the projector is running and the picture starts to dim down to almost nothing, if you select menu or an internal test pattern, are they also dim or are they nice and bright? And if bright, does the regular picture remain dim or come back to bright?
Oh, and is it all 3 tubes that go dim? I assume it is by you description.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Mon Dec 01, 2008 8:32 pm Post subject: |
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| 1031 wrote: | "wrong capacitor"->perhaps bad capacitor.. Have you cleaned that board where those bad/leaky caps was? Electrolyte is conductive so if there is even little electrolytic fluid somewhere on boards that could cause errors.
I have never heard about any Seleco that were made by Nec  |
Sorry for my bad english. I make pictures of NEC/seleco today. I try to clean board as best as possible. Thanks.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Mon Dec 01, 2008 8:36 pm Post subject: |
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| macgyver655 wrote: | Since I'm not exactly sure what projector you have, I'll shoot from the hip here. As the projector is running and the picture starts to dim down to almost nothing, if you select menu or an internal test pattern, are they also dim or are they nice and bright? And if bright, does the regular picture remain dim or come back to bright?
Oh, and is it all 3 tubes that go dim? I assume it is by you description. |
Problem is always here, with pattern and with external picture (RGBHV line doubling). Perhaps video board, it's a pwc-3716.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Dec 01, 2008 10:50 pm Post subject: |
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| Choukard wrote: | | macgyver655 wrote: | Since I'm not exactly sure what projector you have, I'll shoot from the hip here. As the projector is running and the picture starts to dim down to almost nothing, if you select menu or an internal test pattern, are they also dim or are they nice and bright? And if bright, does the regular picture remain dim or come back to bright?
Oh, and is it all 3 tubes that go dim? I assume it is by you description. |
Problem is always here, with pattern and with external picture (RGBHV line doubling). Perhaps video board, it's a pwc-3716. |
If its got a PWC-3716, then its a 6/9 PG.
Your problem could be coming from many various places. Could be Dropping G2 which I doubt. Question is, is it voltage or signal. Since its all 3 tubes its probably not the video board unless its a brightness control issue. Whats comes into the video board? Video comes in separately from the gain board. Brightness comes in from the wave board and drive control comes in from the system board. So as you can see, your problem could come from a lot of places.
What boards did you replace caps on? Why did you replace them? Was there a problem before you replaced them?
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Mon Dec 01, 2008 11:20 pm Post subject: |
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Does the image width change at all when it dims?
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Tue Dec 02, 2008 1:39 am Post subject: |
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| macgyver655 wrote: | | Choukard wrote: | | macgyver655 wrote: | Since I'm not exactly sure what projector you have, I'll shoot from the hip here. As the projector is running and the picture starts to dim down to almost nothing, if you select menu or an internal test pattern, are they also dim or are they nice and bright? And if bright, does the regular picture remain dim or come back to bright?
Oh, and is it all 3 tubes that go dim? I assume it is by you description. |
Problem is always here, with pattern and with external picture (RGBHV line doubling). Perhaps video board, it's a pwc-3716. |
If its got a PWC-3716, then its a 6/9 PG.
Your problem could be coming from many various places. Could be Dropping G2 which I doubt. Question is, is it voltage or signal. Since its all 3 tubes its probably not the video board unless its a brightness control issue. Whats comes into the video board? Video comes in separately from the gain board. Brightness comes in from the wave board and drive control comes in from the system board. So as you can see, your problem could come from a lot of places.
What boards did you replace caps on? Why did you replace them? Was there a problem before you replaced them? |
Caps were replaced on video boards. Electrolytic liquid went out of caps, brown traces on board. Before, trouble with brightness decreasing, after, same problem. It is not caps.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Tue Dec 02, 2008 1:41 am Post subject: |
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| Mark_A_W wrote: | | Does the image width change at all when it dims? |
No change. Same size. Become progressively near invisible.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Dec 02, 2008 4:02 am Post subject: |
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There was a post on here from another member, gregstv I believe, where his PG had no pic and no menu and it was caused by C371 on the system board. His was completely bad but if yours is just failing may cause decreasing brightness. Worth checking anyways.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Dec 02, 2008 4:08 am Post subject: |
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Also, if its not that cap it really sounds like its temp related and probably a cap somewhere. I would get a can of cool spray and try hunting around with that after its warmed up and a dim picture.
Is it consistent, where it almost always dims after 15 minutes or so? How long of shut down before pic comes back bright?
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kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
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| Posted: Tue Dec 02, 2008 9:07 am Post subject: |
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Choukard, where do you live?
Maybe there's someone near you that can help.
Kai
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1031
Joined: 22 Mar 2006
Posts: 657
Location: Finland
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Tue Dec 02, 2008 9:30 pm Post subject: |
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| kschmit2 wrote: | Choukard, where do you live?
Maybe there's someone near you that can help.
Kai |
Hello Kai, I am in France.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Tue Dec 02, 2008 9:33 pm Post subject: |
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| macgyver655 wrote: | Also, if its not that cap it really sounds like its temp related and probably a cap somewhere. I would get a can of cool spray and try hunting around with that after its warmed up and a dim picture.
Is it consistent, where it almost always dims after 15 minutes or so? How long of shut down before pic comes back bright? |
Few seconds after (10 or 15 s). And now, there's no red on pattern ! but red tube run.
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Choukard
Joined: 05 Apr 2006
Posts: 23
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| Posted: Tue Dec 02, 2008 9:34 pm Post subject: |
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| Curt Palme wrote: | NEc made sets for Seleco? Pictures please, that's a new one on me.
I'd suspect a video problem, not a power supply issue. |
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