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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Aug 23, 2008 6:48 pm Post subject: Question for NEC Projector Owners, Past and Present |
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Hi Guys.
The question pertains to the System Board.
I've been working on the system board problems for a few months now. Curt sent me a few PG boards that I had success on and I'm waiting for some more he is sending me, ( Hint, Hint Curt  ). The problem is there are different problems between different boards and different models and I'm trying to get a feel if certain problems are more consistent with specific models.
The problems I had so far are:
1) Scrambled menus.
2) no sync at some or all resolutions.
3) Wont lock to a previous entry that it was locked to.
So what I'm asking is for responses to a system board problem you had. I would need to know, EXACTLY:
1) which model you had/have
2) what problem you had
3) did you get another system board and did it fix the problem
4) if you tried another system board, was it from the same model or a different model and if from a different model, what model was it from.
5) Any info on what model system boards you know for a fact interchange with another.
I have extensively viewed these schematics for all the various models and see circuit variations among them, which is why I need to see if there is a connection between models and type of problem on a specific level.
I would like a response, even if you have 0 technical knowledge. All input is relevant.
Also if you have a non working system board and want to donate it to trying to find a final solution to all the various symptoms, PM me.
Thanks to all who participate.........................................................................
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Heywood Jablome
Joined: 12 Mar 2006
Posts: 1548
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| Posted: Sat Aug 23, 2008 7:06 pm Post subject: |
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I had the described problems with a 9PG Xtra, and it was resolved with a swap of the oscillator board. I'll get a P/N shortly and follow up this post.
--Edit... The 'oscillator board' is more properly the Deflection Board I think.
--Edit again: The board that (for me) resolved those issues described above was PWC-3709(A), and it IS the deflection board.
The specific failure mode was "3) Wont lock to a previous entry that it was locked to." but may have included Scrambled Menus.
_________________
"Those countries which lag behind in industry, in the application of mechanics and technical chemistry, in the careful selection and utilization of natural products, where the respect for such activities does not permeate all classes of society, will unfailingly decline in prosperity. They will sink faster when neighbor states, with an energetic exchange between science and industry, go forward with renewed vitality."
-- Baron Alexander von Humboldt: 1769-1859
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Aug 23, 2008 7:29 pm Post subject: |
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| Heywood Jablome wrote: | I had the described problems with a 9PG Xtra, and it was resolved with a swap of the oscillator board. I'll get a P/N shortly and follow up this post.
--Edit... The 'oscillator board' is more properly the Deflection Board I think.
--Edit again: The board that (for me) resolved those issues described above was PWC-3709(A), and it IS the deflection board.
The specific failure mode was "3) Wont lock to a previous entry that it was locked to." but may have included Scrambled Menus. |
Thanks for the response, however I only need known system board problems. I know there are circumstances where other boards can cause similar problems, but I'm only working on system board problems right now. But again, thanks for your response.
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grogthegreat
Joined: 16 May 2007
Posts: 166
Location: San Diego, CA
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| Posted: Sun Aug 24, 2008 7:17 am Post subject: |
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I currently have a 9PG+. I can't get 720p to work properly on it. 1080p, 480p, and 1024x768 work fine. It usually only happens once the projector warms up. The picture doesn't really scroll but rather becomes what might be described as a scrambled mess. I have not tried any swapping any boards as I'm sure where the fault lies.
If there is anything else I can do to help, let me know. If you start offering repairs I'll probably be one of the first to send my board in.
Thanks,
-Greg D.
_________________
First projector: Sony 1252q with 3500 hours
Second projector: NEC 9PG+
current projector: Sony G90
100" 3:4 draper screen.
I must keep upgrading till the voices stop!!
"I CAN HAZ CRT PRUJEKTER."
-Curt Palme
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Sun Aug 24, 2008 2:27 pm Post subject: Re: Question for NEC Projector Owners, Past and Present |
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| macgyver655 wrote: | The problems I had so far are:
1) Scrambled menus. |
In the XG and I think the PG, the proper technical term for this is "the dreaded scrambled mess." Doug theorizes it's caused by non-zero voltage drops between neutral and ground. He's never found a way to fix it.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Aug 24, 2008 2:54 pm Post subject: |
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grogthegreat, thanks for your response. I'll keep you informed.
garyfritz, theoretical causes and non solutions are not really what I'm looking for. I have already resolved the above mentioned problems on a handful of boards, but I need more boards to verify on and also input on problem verses chassis info, to see if circuit changes that NEC made on the system board had any effect on these issues. A few boards now working does not mean a final solution.
I have had conversations with Doug and others on this issue and I know pretty much what their findings were.
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Brooklyn
Joined: 17 Sep 2007
Posts: 494
Location: Morgan Hill, CA
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| Posted: Sun Aug 24, 2008 6:19 pm Post subject: |
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I had similar problems with my 6PG. It turned out to be a faulty deflection board. I know you are just trying to figure out system board issues, but a faulty oscillation circuit on the deflection board can cause very similar problems.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Aug 24, 2008 6:36 pm Post subject: |
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Yes I am well aware of the PG deflection board and XG Oscillation board problems. It is also my understanding that these board problems have been resolved by replacing some capacitors. So there is not a need to investigate these boards. My project is to find a solution to the system board problems which to my understanding have not been resolved yet other then the experiments I have preformed. The current need of NEC owners is a fix for the system board problems. But thanks for your input.
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sun Aug 24, 2008 9:36 pm Post subject: |
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Mac,
I have a 9PG+ and I have something similar to grog. I don't have any problem with 1080i or 480p that I was using with my Directv box, but going higher would give me the scrambled mess. I haven't tried it in ages, but I believe 720 might start it. I know I couldn't do 1440x960. Turning the pj off and starting it back up would take care of it. I just assumed there was an upper limit on bandwidth before the mess would kick in. My pj is currently not set up, so I could have the system board sent to you if you like. I am curious why you are interested in this.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Aug 24, 2008 10:51 pm Post subject: |
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| Spanky Ham wrote: | | I am curious why you are interested in this. |
I guess it's because I'm addicted to solving things that others are unable to. Been that way a long time. Since I have a lot of free time now, I look for these projects. Last fall I remember someone with an Ampro CPU board problem and not many to help. I talk to Scott and he sent me a bunch of non working cpu boards, I bought a programmer and a bunch of chips. I spent many hours viewing schematics and getting a mental view of the entire cpu board. I was then able to repair all boards and make copies of the software for the various boards I had. I now feel I can repair any problem on the Ampro cpu boards. After I finished that project I was looking for my next and seeing how I want to keep CRT projectors hobby alive I wanted to choose a problem that alot of people seemed to have and there was no repair for. Hence the common NEC system board. And I dont take these problems lightly. I would estimate I have probably invested 100 to 300 hours on this project, with a good understanding of the system board but not enough boards to verify a fix on.
By using Thomas Edison's philosophy, I have found 30 to 80 things that do not cause the problem. 
But as I also said I have had success on a handful of boards.
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Mr. Green
Joined: 23 Feb 2007
Posts: 1394
Location: Calgary
TV/Projector: Marquee 9501LC / NEC 9PG+
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| Posted: Wed Aug 27, 2008 3:23 am Post subject: |
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I have zero experience with what boards do what, but I'll toss in my 2 cents.
I too have a 9PG+ and unlike Grog my projector can't see(?) 1080P. 1080i works great, but since there are often menu's at different resolutions it will often sync to another input after it's had to cycle a few times. I just make sure to re-select my 1080i input once I know it will stay there for a while. I guess once I have my setup down to a few inputs, I'll just delete the others to avoid the problem as stated in evry set-up guide on here.
One other problem I seem to have is the red tube on menu's seem to "bleed?" I can take a photo if necessary. If it's not system board related I might get Curt to look at it.
_________________
You can be young only once but, you can be immature forever.
Current Projector Marquee9501LC with PS3 (BLu-Ray) at 1080P LOVE IT! Screen is an Elunevision 120" 4:3 (2.4 gain - no hotspots). (also own a NEC 9PG+)
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Wed Aug 27, 2008 5:53 am Post subject: PG9+ |
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I had a problem with a PG9+.It had no picture and no on screen menu but the tubes were all lit.
Turned out to be C371 on the system board was leaking and had eaten some of the copper track under it.
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dropzone7
Joined: 12 Jun 2007
Posts: 1069
Location: Charlotte, NC
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| Posted: Wed Aug 27, 2008 2:20 pm Post subject: |
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Well, you probably remember my experience with a system board scrambled mess and no sync problem. That was on the XG-852 projector I'm currently using. After a board swap from another XG-852 with identical system board part number, I was up and running again. That suspect board went to Curt and I told him if it was indeed bad that he could keep it for study. I'm assuming he sent it to you based on your comments in the original post but perhaps not. Of course, I have this XG-110 unit here with no issues that would make a good test chassis for you. I have never had an issue with it's system board or any other board in it. My first thought when I had issue with the 852 was to swap the system board from the 110 into it but of course the part number was different and I didn't take a chance on trying it. I was lucky to find someone locally that had my specific board part.
_________________
"Coffee is for Closers."
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