NEC 9PG service manual - AVS Forum
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post #1 of 7 Old 05-01-2013, 08:54 AM - Thread Starter
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I couldn't resist buying this NEC PG-9000 (9PG) when I saw it for a giveaway price. The CRTs look mint, and it reports less than 3000 hours on it.

Initially, it had severe vertical distortion, but replacing a bunch of leaking caps on the deflection board fixed that. Now it syncs to the RGB input, but the picture is narrow with keystone distortion, and the width control in the menu has no effect. It won't sync at all on the video input. Even with no signal, it cycles between different scanning modes making the OSD impossible to read most of the time. Surprisingly, connecting composite video to the green input syncs fine, and it had full width last time I checked. This would lead me to believe it's not a problem with the deflection board.

I've found a few more bad caps on the boards inside the shielded box that I will change today. I also need to take a closer look at the more hidden boards for bad caps. Even if that fixes it, a copy of the service manual would be handy. Does anyone have a PDF they would be willing to share?
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post #2 of 7 Old 05-02-2013, 07:04 AM
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It probably has no video input card. Keep recapping. I've stopped repairing these sets due to capacitor issues that wou;d take far too long to repair, never mind the other boards that also have dozens of leaking caps. Leaky caps have been known to eat away board traces on NECs as well, so look for that too.

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post #3 of 7 Old 05-02-2013, 10:22 AM - Thread Starter
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Quote:
Originally Posted by Curt Palme View Post

It probably has no video input card. Keep recapping. I've stopped repairing these sets due to capacitor issues that wou;d take far too long to repair, never mind the other boards that also have dozens of leaking caps. Leaky caps have been known to eat away board traces on NECs as well, so look for that too.

Where is the video input board located? There are two boards under the shield, one is the output board with the large heat sink, and the other is in the middle slot. I assumed the middle one was the video board since it has a 3.58MHz crystal on it. The slot closest to the back is empty. If that's where the video board should go, would you have one you could sell (assuming I can fix the horizontal issue)?
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post #4 of 7 Old 05-02-2013, 11:14 AM - Thread Starter
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Never mind, I see that the rear slot is where the video board should go.

I get full width with control in 480i, but all other resolutions are narrow with horizontal fold over. Even at 480i, there's a large bump in the raster along the edge.

I can't find any more leaking caps, and I haven't found any open traces. The problem may well be caused by caps, but finding it without a schematic won't be worth the time. I'm not even going to consider a full re-cap until it's working well enough to know it won't be for nothing. If anyone has a schematic they are willing to share, please let me know.
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post #5 of 7 Old 05-02-2013, 02:07 PM
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that's just an expansion slot. The video board is show in these pics ,it's under a sheet-metal

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post #6 of 7 Old 05-02-2013, 05:58 PM - Thread Starter
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I've made some progress with it. I found a schematic, and I confirmed that the width circuit seemed to be working more or less. I did do some more board clean up, and I initialized the EEPROM settings. Now I have a decent display at 480i, 480p, and 1080i.

720p is about 25% narrower than the other modes, and the width control only has an effect up to mid range. Beyond that the picture stays the same. I assume that's not normal. 1080p is even worse and has fold over on both sides. Based on the specs it seems that it should be able to scan 1080p with no trouble.
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post #7 of 7 Old 05-03-2013, 09:59 AM
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fold over at 1080P on these sets is normal, it cannot do 1080P. not sure what's going on with 720P,but most people will tell you 1080i is the sweet spot for this machine.
If it was a PGX then 720P is a little better IMO.

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