CurtPalme.com Home Theater Forum

Zolzar · Joined: 26 Jun 2009 Posts: 252

I turned off the AKB in the menu and it did not eliminate the issue with the blue drive. Forgive my ignorance but is there a physical cutoff switch anywhere? Since it is only a problem with the blue drive what board should I examine? Video PWB? There is the distinct possibility this loss of control is due to an error while changing out the caps.

Thanks,

John

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

Indeed, Video out PWB measures the tube current and can cut off the drive. TP3402 is the test point for blue tube current (TP3202 for green, TP3002 for red) You'd need an oscilloscope to examine these signals with eg. a full white test pattern. Of course these values shouldn't be the same, but will give an idea if the blue tube is really driven that hard, or the projector just thinks it is driven hard... As you probably noticed there are quite a few adjustments on that board and any of them could be connected to your problem, as the relation between the controls is very sophisticated.

Zolzar · Joined: 26 Jun 2009 Posts: 252

I do have a scope so I can take a look at each. Thanks for the heads up on the test points. I also have the service manual so there should be something in there about the process......a process I'm sure is not easy to fully understand and can possibly lead to more problems. The first thing I will do is check my work on the board concentrating on the blue section. I could have accidentally hit one of the little pots on there too. I'll see what kind of time I have available over the weekend to dig into this. Thanks again!

John

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6319 Location: Australia

I wonder if someone molested the G2 settings on that?

Zolzar · Joined: 26 Jun 2009 Posts: 252

Given I am only the second owner and the original owner had it calibrated professionally I would doubt the G2 theory....however....G2 levels could still be an issue since when the picture muted the raster does not completely turn off. What do you think?

John

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

That could be a clue, normally when the picture is muted, you should only see the raster when looking in to the lenses directly, what are your brightness and contrast settings?

Zolzar · Joined: 26 Jun 2009 Posts: 252

I should have been clearer on my description. It is only when I look into the tube that I see the raster.
Contrast 75
Brightness 48

My biggest problem while setting up the grayscale was the blue tube drive. I order to compensate I had to drop the green drive to 50. I did not want to do this but this is the only way I could get all three tubes within 1% of each other on 30 and 80 IRE.

John

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

I think the kelvin settings should be more in the 50ish range rather than in 70-80. Take a look at the HV power supply board if there is a switch on it (hormal/high bright) don't hesitate to switch it to high bright mode, 10PGs are not the brightest pjs amongst 9-ers, maybe you just pushed it too hard.

Tinman · Posted: Fri Feb 22, 2013 7:30 pm Post subject:

Green is usually at 50 - 50 and then set red and blue for grayscale. On the PG10 make sure the switch on the HV board is set for bright. I'm not going into the actual pot adjustments on the video out board since this is too complicated for most people to do, but that could also be the problem. Make sure you see where the tubes are in TEST mode on the video board. If everything isn't close in test, the board probably needs re-alignment. The 3 pots on the G2 module should all be set the same, or VERY close visually. Pushing the tubes too hard with the HV switch in low mode can cause pulsating.

Marc

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6319 Location: Australia

I am not sure where my KELVIN settings are on th 9PG, all are under 50, on my XG the red is in the 10s, the other two are in the 20s... 100" 4:3 for the 9PG, 125" 5:4 for the XG, more than bright enough!!

Zolzar · Joined: 26 Jun 2009 Posts: 252

I tried the bright switch and found it to be set on high already. I will pull the video board later today and check my cap work. If that isn't the problem I would like to take the next step in checking the pot adjustments. I'm not afraid to make any adjustments using a DMM and scope. The only way to learn it is to do it.

John

Tinman · Posted: Sat Feb 23, 2013 5:49 pm Post subject:

Zolzar · Joined: 26 Jun 2009 Posts: 252

I do have the service manual with the procedure. I read through it and my biggest problem is that I don't have an extender board. I'm getting a little ahead if myself as I still need to look at my work very closely.

John

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

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6319 Location: Australia

I dont see why youd have to have the settings up so high, should be way lower than that, which is why id check the G2 pots first cause i reckon if you need the KELVIN up in the 80s the G2 is probably too low.

Zolzar · Joined: 26 Jun 2009 Posts: 252

All of my W drive setting are right around 50 for each tube. Are you saying my contrast setting shouldn't be so high? I also did look at the G2 pots and they are all in the same position.

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

Zolzar · Joined: 26 Jun 2009 Posts: 252

I just wanted to follow up on the problem I was having with the Blue drive. It is repaired and has been for a while now. I found the problem in the re-cap job. I failed to install a capacitor on the blue drive op amp follower. Without this cap clamping down on the follower it caused an oscillation in the tube drive above a certain level thus limiting the adjustment range. All fixed!

Curt! Old thread here but the case I received the PJ in from NEC did say prototype on it. I do still want to take some pics and post them and see if there is anything special about this projector.

Maybe the serial number can provide some clues. #7300111 Anybody have any thoughts on this number?