CurtPalme.com Home Theater Forum

RayN999 · Posted: Tue May 25, 2010 9:41 pm Post subject: NEC 9pg with a puzzling problem

I'm newly registered but I've lurked here (and been a CRT nut) for quite a while now.

I picked up an NEC 9pg off CraigsList last holiday season for free, $0.00. Owner originally said it didn't power up, but then got it to fire up in the time it took for me to get from my place to his (about 20 min. drive). He said it was stored in his garage for a few years, but wife was sick of stepping around it when getting out of her car every day.

I ran through the guide on here, did discover that it was set for ceiling mount, swapped it for standard since I had it on a cart, only possible place to put it for time being. According to the hour meter, it has only 800+ hours on it, and when I pulled the lenses to look at the tube faces, there's very little wear on the G & B and none on R.

Originally things seemed to be mostly fine with it and I was able to get it converged & set up an input for it & got it to display 720p & 1080i without any problems.

Last week when I fired it up to get some settings verified & take some pictures for the buyer, I'm getting some strange problems that I'm calling upon the wisdom of the great people here for help & guidance

Projector now fires up, displays 'no matching input' until I get the PC running (normal), then it'll lock to 1024 signal, 1024x768 at 60 hz.

If I attempt to step it to 1280x1024 or 1280x720 at 60 hz, the 'h-fail' LED immediately comes on & projector shuts down with an 'F3' alternating with '00' on the LED panel.

I've reseated the system boards inside the card cage, but that hasn't changed any issues. The F3, according to the error list, seems to point (no pun intended) to the 100 point convergence board, but that doesn't really make sense.

Also, after a few min. the raster seems to 'flicker' to the left slightly (but not going off tube face, I have the rasters dialed down to prevent this for time being). But I think this is just a symptom of a dirty H width control pot on the deflection board.

If any of you could help point me in a direction to go, I would greatly appreciate it.

Thanks,

Ray Nelson

**Curt Palme** · Posted: Tue May 25, 2010 10:07 pm Post subject:

Chances are you have a bunch of problems in the set. I recently spent 5 hours working over a 700 hour PG projector, changed about 25-30 parts, it ran fine, then broke down again as I was installing it. Back to the shop, changed 10 more parts, ran it overnight, and installed it. I'm heading out tomorrow to do yet another service call on it as it's dying 15 minutes into a movie.

THe thing is, these PG sets are now 17ish years old, and even at 0 hours, parts are failing due to age. I could rework a bunch of the boards for you, but you're looking at $250-300 incl return shipping just due to the time involved to test and change a bunch of parts on multiple boards.

RayN999 · Posted: Tue May 25, 2010 10:35 pm Post subject:

Sounds like I would be better off salvaging the tubes & lenses and scrapping the rest.

Anyone wanting NEC parts?

Ray

paw · Joined: 08 Mar 2006 Posts: 1176 Location: Arvada, CO

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

RayN999

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

I would not start out at 1024. Start at 480p. And let it run for hours and hours. If no problem then increase it to 800X600. Again for hours and hours. The to 720, then 960 and then 1024. Hours and hours for each. Just be sure to turn down the contrast and have moving video.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Oh, and dont bother making adjustments. Just let it run. Leaver it alone. The only adjustment to make when changing resolutions is to make sure the image in not running off the tube face. But if the image is small, just leave it alone for now. No geometry, no convergence, nothing. Just let it run.

RayN999 · Posted: Wed May 26, 2010 4:12 am Post subject:

Ok, thanks for the suggestions. I've not made any geometry adjustments at 1024 yet other than a very quick (and messy) convergence in center just so I could see the Windows desktop "properly". I have a PC hooked to it, so running some video at various resolutions isn't an issue at all.

I'll step it back down to 640x480 & start from there.

So far all of the resolutions I've tested have remained close to the center of the tube face, I haven't cranked up the rasters to get near to any edge of the tubes.

Thanks again....

RayN999 · Posted: Wed May 26, 2010 11:37 pm Post subject:

I ran it today for a few hours at 640x480 as was suggested by a couple of people, then stepped it up to 800x600 for a while longer. I had the brightness & contrast cranked down to 30, ensured rasters weren't getting close to tube edges, and it seemed to be stable. However, as soon as I tried to move it to 1024x768 at 60 hz, it shut down again with the H-Fail LED illuminating on the deflection board.

Seems that it can only find value now as a parts machine. I have no idea what to value the components at, so I'm sure someone will get one heck of a steal if they want tubes/lenses from it.

Thanks again

RayN999 · Posted: Mon May 31, 2010 4:51 am Post subject:

On the off chance (and just for giggles, only wasting $15), I picked up a replacement Horiz output transistor. The deflection board may have issues other than this, but I figure it's a place to start.

Going to try installing it in the deflection board tomorrow. If I get lucky, it'll get the 9pg back to functional shape. If not, I'm out $15.

deronmoped · Joined: 03 Nov 2006 Posts: 1154 Location: San Diego

Mark_A_W · Posted: Mon May 31, 2010 9:39 am Post subject:

They don't work as hard Deron.

The deflection and cathode driving circuits in CRT projectors work very hard.

Other than that....well, despite the price, they sometimes used crap parts. And SMT was immature at the time, it craps out.

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

Yes Deron i was wondering that myself, my 9PG is a 92 model, and has zero wear, says its done 3,994 hours, and works faultlessly. I dont know for sure if the caps are original, cause they are all 105* caps, and i was recently told by a mate that also has a 9PG that he had a feeling the caps originally had a slightly lesser temp rating... Either way, no leaks, no signs of age, still looks and works like youd expect a near new unit to work.

Lets hope it stays that way!!

Mark, what is SMT?

RayN999 · Posted: Tue Jun 01, 2010 6:41 pm Post subject:

SMT = Surface Mount Technology, a variety of small parts that attach to one plane of the circuit board instead of "through hole" parts. They usually are quite small & require a different skill set to repair.

I've constructed a couple amateur radio kits based on SMT, and a magnifying 'hat' (wife calls it my "evil mad scientist hat") with light & magnifying lenses is an absolute must, even for someone with 20/20 vision like myself.

Well, after replacing the horiz output transistor, the projector fired up seemingly without a hitch (for now). I ran it at 640x480 & 800x600 for a couple hours this morning and it was totally stable. Bumped it back to 1024x768 and that also seems rock solid.

I think I fixed the problem I was having, now to see if my original party is still interested (or see if wife will let me keep it for myself)....

Thanks for the ideas & help everyone.

update: It's up & running at 720p. Playing a blu-ray movie on it now, and it looks stunning....

Thanks for the suggestions everyone.

Ray

RayN999 · Posted: Thu Jun 03, 2010 9:29 pm Post subject:

Since I took care of the problem, figured I'd "join the club" and pay my dues. Looks like I won't be a CRT owner for much longer, but I'll still aspire to possess one when we manage to get a house with enough room for me to dive back into the CRT goodness.

It's still working fine, looks like the transistor took care of the issue.

Ray

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

**AnalogRocks** · Posted: Fri Jun 04, 2010 1:39 am Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

RayN999 · Posted: Fri Jun 04, 2010 3:11 am Post subject:

I would've considered that it may not have been bad, but when I put the new part in & got an immediate difference.... Well, it was just easy to pin that part as the faulty one.

During removal I had to snip one of the old transistor's leads a bit short to remove it after I got the other 2 leads out. It would've been an interesting time putting the old part back in, but I'm pretty sure it was the source of my issues.

Thanks for the suggestions though.