CurtPalme.com Home Theater Forum

Rattanee · Joined: 18 Jan 2015 Posts: 193

Hey guys, been way too busy lately to come around much, but I got my hands on yet another NEC, and I am curious.

I have two PG9 sets, and now picked up a PG6 Plus. The Plus seems to be much more refined then the simple version (Degaussing, HD-145 lenses, adjustable lens flapping instead of spacers... and astigmatism to boot...), and I am wondering what the differences are hardware-wise. Specifically, I'd be curious to know where the maximum frequency is determined by these projectors. Is turning a PG6 into a PG9 as simple as swapping the deflection board, or the main PCB ?

What I'm getting at is, would it be possible to turn the PG6 plus into a PG9 plus fairly easy? (Burning eproms etc is not an issue.)

Thanks for any help on this

**Curt Palme** · Posted: Fri Oct 23, 2015 12:04 am Post subject:

No, not easy at all for the PG to PG+

Different:

-system board
-deflection board
-astig board
-different focus board and wiring harness

6 to 9. I believe it's only the system board that's programmed different through the EPROMS, but I know the deflection board has different numbers as well. NO point really in a 9Pg, the tubes can't resolve 1080p anyway, so 720p on either the 6 or 9 is the best.

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

There is an UV-EPROM on the system board which needs updating, and there is a Hybrid-IC on deflection board that differs. Of course you can't mix EPROMs between PG plain and PG plus, however you can reuse the hybrid ic on the deflection board.
You might want to check this thread: link

Rattanee · Joined: 18 Jan 2015 Posts: 193

What about the point PWB? Will the Point from a plain work in the plus, or would I need a firmware update for that too?

Thanks for the info gjaky, from what I gather, if I can get the eprom data for the 9pg plus system board, and swap the hybrid IC on the def board, the pg6 plus will essentially work as a pg9 plus right?

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

Rattanee · Joined: 18 Jan 2015 Posts: 193

So I went ahead and gave the PG6plus a test-run today, and I ran into some issues. Would anyone happen to have a service manual (schematics!) for the plus?

The PJ turns on, but at first I thought the blue tube had horizontal collapse (would've been a strange symptom...) but it turns out it's just pretty dim, and on putting up the white square test pattern, only the edge of the square on one side is visible, resulting in a single vertical line. So no collapse, but colors ain't right at all...

Problems:
All OSD menus are very dim! I can see them, they are all there, but are barely visible.
Putting up the crosshatch pattern, the pattern is okay on green.
Blue and red were very faint though. I created a new input with all settings normalized, and on crosshatch, the red and green came up as well, but in a funky sort of way... the vertical lines are strong, but the horizontal lines are barely visible if at all...
Opening the qhite square pattern, the green tube displays the square with the left side having a noticably stronger vertical line. On red and blue, only the line is visible, the square itself is not. If I crank cutoff for those tubes up in the menu, I can get a gray square at best...
Applying a video signal, I get a picture with way too high contrast...

The PJ may have something funky going on, as the internal clock had a = symbol in the minute counter... ??? What's up with that? I'm suspecting some of it's memorized data may have gone corrupt in storage, affecting the video setup too ? Is that possible? What would be the best course of action to restore it?

Thanks for any help guys

**Curt Palme** · Posted: Sat Oct 24, 2015 1:00 am Post subject:

If Kal has the manual on file, he can throw it up, as with the PG, but very little was released on the PG+ I think, since it was pretty close to the PG overall.

Just beware that you're really spending a lot of time on a set that is now ridiculously problematic due to leaking caps. Any weird (or 'normal')problem has the same answer: Recap every electrolytic on almost every board. Most NEC issues now involve multiple boards, as when you fix one, it then affects another. I've seen this many many times, to the point where i stopped supporting NEC PG sets, period. even my test set, that worked fine, and hadn't been used in about 8 months died, and had all sorts of issues with it when I last fired it up 3 years ago. I spent 4 hours trying to get it going, and that's when I finally gave up.

It's great that you want to get yours going, but it really is pointless. Find a cheap Barco or Marquee, or even NEC XG set, which is not showing the same signs of age as the PG series are at this point.

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

Rattanee · Joined: 18 Jan 2015 Posts: 193

Gjaky sent me the manual, thanks!

Recapping isn't that big a problem Curt, I've done it on a 9PG already, and since I have a discount going with a parts supplier, a complete cap kit with decent caps is $50 tops. Though in this case I'm suspecting this may be a memory related problem with the settings being jumbled, as all functions work fine, and even the composite input doesn't give the 45° 'crosshatch' effect that I got with the 9pg that had failing caps. Though quite possibly a set of decoupling caps went where the OSD video info is fed into the video output. Yet another project to tinker with during the winter Smile

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

Well, actually you can put the VIDEO OUT board in from the PG plain to the PG plus, they are the same.
I really think you havel leaking caps on system board all over... Otherwise you can try EPROM reinit...

for this:
Set up a user passcode, like 1234. Then go back to user mode and enter in to expert mode with master passcode 2580, then you'll have an additional ref. adjustments item in adjust menu. And there is the EPROM reinit option. This reverts all settings to factory default.

**Curt Palme** · Posted: Sat Oct 24, 2015 4:59 pm Post subject:

Rattanee · Joined: 18 Jan 2015 Posts: 193

[quote="Curt Palme"

I still think it's caps. I've NEVER had EPROM problems in an NEC, although there's always a first time, right?>[/quote]

I just did the video out board yesterday evening, replaced every cap (did find a few that reeked of lyte, though nowhere near as bad as my first pg9). Fired it up just now, and no change at all. Will do system, then gain ctl next. I'm suspecting memory because there was a = in the minutes field in time... then again all the input list items seem to be intact...

Rattanee · Joined: 18 Jan 2015 Posts: 193

Video Out, System and Gain CTL pcbs completely recapped. Virtually no change. Setting menu to 'color' mode brings up the menus much more visible in blue and red... I am now fairly convinced someone turned the colour balance trimpots on the video out board... :\ Time to look up the calibration procedure... *insert cussing here*

**Curt Palme** · Posted: Mon Oct 26, 2015 11:14 pm Post subject:

Let me know if you figure that out. I never could.

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Rattanee · Joined: 18 Jan 2015 Posts: 193

Well I did read the 'how to' in the troubleshooting manual, but yah... no colorimeter... so best I can do is eyeball it... which will probably be less then satisfactory... :\

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Okay, I misunderstood. To do that you would need an osziloscope and you would know how to handle it. Used budget colorimeters are basic for CRT useres anyway and you can get them starting at $20 (second hand budget colorimeter incl. free HCFR software).

Rattanee · Joined: 18 Jan 2015 Posts: 193

I have a 100mhz Gould DSO so that's no problem, but I'm not at all familiar with colorimeters and their workings. The service manual has reference values for an x and y axis for a weird interpretation of RGB values, and I'm not sure what meter I could use to get data as such. Any suggestions? I'm game for getting one, as you said, nothing to loose with this video out board, so might as well give it a shot.

Rattanee · Joined: 18 Jan 2015 Posts: 193

Well... the problem is certainly not the video out board... :\ I finally got out to my workshop and pulled the video out from my backup PG9. Installing it into this PJ (I hate the cable routing for this board more and more with each removal...), I'm getting pretty much the same results... (a little darker overall, and there's no red or blue menu, only a very faint green, but generally the same...). This video out board is 100% working. Ergo the problem is not in the colour drive circuitry...

Someone -please- tell me there's something else in the OSD path between the system main and the video out board... based on my digging in the schematics, the osd video signal goes straight to the video out board from the system main board...

Will I fry anything if I put the system board from a plain into a plus for diagnostic purposes? I'm suspecting the system main is hosed...

I cloned one of the video modes from the input list into another position, and set kelvin levels to be -very- roughly okay. After a reboot, all the kelvin data is displayed as set on center, regardless of which of the two video modes is selected, but there -is- a difference in colour balance... also, pressing the kelvin button makes the screen a lot brighter... am not sure if the latter is normal ?

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

I don't think the system boards are interchangeable. install some flywires on both system board and video out on the OSD signals and check the signal wit oscilloscope.

Brightness and the kind sliders have no real meaning in the software all of these are governed by AKB (Auto Kelvin Balance), which automatically initiates when you push Kelvin (note the odd line on the top of the sreen). AKB sets the brightness values to a reference value (potentiometer on Video out). The purpose of AKB is to maintain "constant" cathode current ruling out electron gun aging.