CurtPalme.com Home Theater Forum

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

Hi all, I'm new to CRT projectors.

A few months ago, I've bought a (modified) NEC PG9000, basically for scrap metal value.
The tubes are good, green tube is about a 7 on the scale of 10; R and B look even better.
A previous owner added chassis fans on the bottom and small fans to the ...... is that the deflection board?

After disassembling half the projector because of a dropped screw I've finally set it up, and tried operating it three days ago.
I've succeeded in basic convergence!

There's some minor things I haven't figured out yet:
1] Sometimes the menu scrambles. Sometimes it doesn't.
2] The PG takes its time.... 30 ~ 60min ... to fully warm up.
The first 15 minutes the picture is pretty unwatchable.
Then bit by bit it comes into convergence (ssllloowwwwlllyyy)
Eventually it will be very sharp Wink

3] The PG doesn't seem to be very happy at 1280+ by [whatever] resolution @ 72+ Hz.
(this actually is not an issue, as my eyesight is not good enough)
4] The PG chooses weird memory blocks while in process of warming up, or doesn't recognise anything at all.

I think it's related to old capacitors (hope I get to find out where to start or what to check)
Or maybe because the PG has just been sitting somewhere for a very long time.

I've read here on the forums and found similar problems with NEC. Still lots of reading to do.
I haven't used point convergence yet (set to disabled). Maybe I'll try later on.

So far, this little PG has impressed me. Yes it did.
Many thanks to Kal for writing an instruction and to Curt for hosting it on a website.

Audiophile · Joined: 23 Jun 2012 Posts: 29 Location: Manassas, VA

What are you feeding the projector - Blu-Ray, line doubler, HD Satellite? Any screen shots?

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

So far I've used my existing "multi media pc". It runs diskless (iSCSI) Windows XP.
It it configured for 1024x768 @ 85Hz with NVidia Fx6200 graphics card.

The sound runs digitally to my Denon DAC.
Then the Technics amplifier and Mission speakers.
Then an equalizer and limiter/compressor (for nighttime watching).

A screenshot is in the first post.
I'll probably have to do some fine-tuning the next few days.

One thing to keep in mind is that the PG needs 30+ minutes to warm up.
Figuring all those alignment and convergence controls out was pretty hard while the pictures were still drifting.

Yes, you can laugh now Wink

Tinman · Posted: Sat Jun 30, 2012 7:42 pm Post subject:

The drift and most other problems are usually caused by dying capacitors.

I no longer work on projectors, but wrote a nice guide on the proper alignment of these. Look for the "Tinman and Feathers" guide someplace here.

I'll refer you to Curt for fixing the capacitor issues.

The PG will take 720P, but I wouldn't run it higher. I gave up my Runco990, which is actually an NEC PG10 that I modified. In the end, driving it with a HTPC was just too much trouble, though it was breathtaking with Bluray at 1080i. I needed the computer solution for other reasons, so went to a digital which gives me no fuss whatsoever, but at a slight sacrifice in pure image quality. I'll live with it.

Now if you can get 1080i to work out of your computer, the PG will love it!! (I could not, to save my life!)
I think it's the best resolution to run it at, period. Also does not stress it too much, so less drift and heat.

A really solid PG still needs some time to "come alive" as the picture goes, but drift should be minimal to none.
Proper setup is critical for this, though. Not just good caps on the boards.

Marc

**Curt Palme** · Posted: Sat Jun 30, 2012 11:12 pm Post subject:

I'll add a bit.... Those sets are now approaching 20 years old, and yes, capacitors can cause drift. It's pretty much a matter of replacing electrolytics on the boards. It sounds like you know a bit of electronics, your screen shot looks fine If you know how to solder, look for electrolyte coming out of the bottom of the caps, those are the ones to change. The problem can virtually be on any board. For something like this, it's not really worth sending into me, since I could spend hours on a board changing caps, and it still might not fix the problem.

So change maybe 5-10 caps at a time, then power up to make sure everything is installed OK. Nothing worse than replacing 50 caps, then finding out the board now doesn't work, and you don't know where to start looking. Sad

The intermittent locking of the signal and the scrambled menus is a problem on the system board which may or may not be solved with changing caps. All you can do is try.

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

Thank you for the suggestions, hopefully I can keep the PG running and also improve the electronics over time.

I'll also try and find out more about interlaced video output from NVidia cards. I think it can be done. I used to have a Matrox card that could be tweaked into almost any possible configuration.

Phoenixed · Joined: 13 Oct 2011 Posts: 514 Location: The mitten

Don't worry Fuchs. No one will make fun of your setup. You gotta do what you gotta do simple as that. If your happy with your setup that's all that matters. Welcome to the forum.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

I have the same model in my bedroom, ive had it 5 years now. I had to repair it before i could use it cause it wouldnt lock onto signals, but that wasnt had to fix, and it has been bullet proof reliable since then, with the only failure being a system board. I have 4 more spares. I found the locking onto signals issue on the DEF board with leaking caps and "previous owner adjusted" trimpots. At certain resolutions mine would just be all scrambled.

I dont have any issue at all with drifting convergence on my PG, my XG i have a slight misalignment of the red when its first started, but the PG there is no noticeable movement at all, and i must say there never has been. I did have an issue with brightness of the red tube a while ago but that went away after i replaced the rest of the capacitors in the set, and has been perfect ever since. The moisture in the air here may have had a hand in that issue at the time too.

There may be better projectors out there, but these are an exceptional machine, and with the point convergence you can get the geometry and convergence pretty much 100% perfect.

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

Thanks for the kind greeting and suggestions!
Okay, I've been playing a bit with different resolutions and refresh-freq's.

The internal NVidia driver kept insisting my "monitor" doesn't do interlaced video.
But managed to get the computer to output interlaced video with Powerstrip, probably not unknown to you.

With 1080i @ 50 or 60Hz the image looks good, but the flicker reminds me of my old '80s TV. I did not like that.
At 1080i @ 85 Hz the flicker was gone, but the horizontal lines of the Windows desktop were still "jumpy". It still reminded me that it was interlaced.

Another quirk of interlaced output was that the Windows desktop looks okay, but the overlay picture (the movie) is doubled in height, so I see only the upper half, and stretched. This obviously is a driver<->player mismatch, but I couldn't yet check how movies look like in interlaced output.

I'm not sure if I'll go ahead with interlaced, maybe there's "anti-aliasing" style options.
Maybe I'll just have to get used to it a bit, possibly it's not that visible at all in a movie.

I'll start looking into changing the deflection board caps in a few days/weeks.
Right now I want to check if this machine is reliable enough to put a lot of effort in.

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

on a side note: I was reading this post (and others on the topic of standby mode).

It seems that on my NEC the "standby" function powers off the tubes entirely (as would seem logical to me)

Someone mentions situations of 3500 hours of tube on / picture on, and 70k hours of tube on / picture off.
But .... why would anyone run a projector with the picture muted for 70k hours ?

Phoenixed · Joined: 13 Oct 2011 Posts: 514 Location: The mitten

We have talked about this a lot. Maybe someone didn't know the pj was still on or maybe they needed it to be "woke up" instantly. OR companies just didnt care.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

That is probably some burn in, youd be able to see better if you remove the lens, and it may even be just abit of dirt.

Point convergence is awesome Wink

Tinman · Posted: Mon Jul 09, 2012 8:34 pm Post subject:

Make sure you do NOT over-use point convergence. Get it as tight as absolutely possible with regular first.

Too much point causes problems.

Marc

**Curt Palme** · Posted: Mon Jul 09, 2012 8:49 pm Post subject:

What MArc said. You should get the convergence to within 2 test pattern line thicknesses anywhere in the screen.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

fuchs · Joined: 27 Jun 2012 Posts: 153 Location: the NL

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

I'm not sure, but I think you can zero all point settings with pressing the CTL+NORMAL key combo while you are in point convergence mode.
Too much point convergence can cause picture banding (certain bands on the picture will be notably brighter, while others will be darker), the other thing I know is the point convergence system is not implemented in the best way to the convergence path making it unstable (eg. the precision is more heat dependent than the normal convergence adjustments)