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NEC PG xtra potential problems
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Thu Sep 25, 2014 5:16 pm    Post subject: NEC PG xtra potential problems Reply with quote


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I am pretty new to the CRT projector scene. I just set mine up a nec pg xtra. I have got a pretty good picture out of it but it seems as if it might have some problems.

When I power the unit up i notice the red tube lights up and projects a full red screen well before the other tubes even turn on. the full red screen lasts for about 3 to 5 seconds. I wouldn't think this is normal. what would be the fix to this?

I have been running the set at 720p with good results. I know people say that this machine is best at 720 but that it can also lock onto 1080. I would like to see which I like better but every time i try to feed it a 1080 signal it does lock to it however it starts making some noise which i cannot imagine being good. I am guess the noise is coming from the power supply. it sounds like it is coming from an area right below the blue tube.

Also, anytime I try to adjust the contrast brightness or any off the kelvin controls I seem to have issues. the issues could range from the brightness increasing on its own suddenly to varying the colors, making the image pink then green then back to pink and basically flashing different colors.

Lastly, the set just started having some jitters or shakes only on the blue tube.

I would be pretty certain something must be wrong here I just dont know what. I have two other incomplete units that I could use for parts.
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Thu Sep 25, 2014 7:34 pm    Post subject: Reply with quote

Problem a.) and c.) are probably are related, check the neckboards' connection to the VIDEO OUT board, especially the wide connector, with the colored wires, reconnect them a few times, it might help.

b.) Exactly what kind of noise is coming from under the blue tube, like screaming? Probably you have some weak parts/solder joints in the LVPS. Personal advice: if you can, try 1080i-60/72/96Hz as well.

d.) Try to reconnect the bule tube's deflection yoke connectors (on DEF board) a few times.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Fri Sep 26, 2014 2:06 am    Post subject: Reply with quote

the noise is more like a hum not really a scream.
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Curt Palme
CRT Tech



Joined: 08 Mar 2006
Posts: 24296
Location: Langley, BC

TV/Projector: All of them!


PostLink    Posted: Fri Sep 26, 2014 2:10 am    Post subject: Reply with quote

You're probably OK with the hum, you're really pushing the set pretty hard at 1080p. also try 1080i, you might like that better.

as for the color balance, you need to store to memory once you're in the Kelvin/color balance menu. that should fix that red issue. Whatever you do, do not adju7st the little trimpots on the video boards!
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CasetheCorvetteman




Joined: 09 Nov 2008
Posts: 6319
Location: Australia


PostLink    Posted: Fri Sep 26, 2014 7:39 am    Post subject: Reply with quote

Its my opinion, but 1080i does look nicer than 1080p on an XG, so youd be in the same boat there. 1080p is abit much for this machine.

The shaking is very likely to be just what Gábor said, its no big deal, just clean the large four pin yoke connectors on the DEF board.

Im quite inclinded to agree with Gábor also on the point of brightness going up and down being a bad connection somewhere in the set related to the AKB, but i would also turn that off in the menu as well, its quite normal for the bightness to fluctuate briefly when the KELVIN menu is entered into, however it should only do that once, not continuously.

As Curt states, dont touch the trimpots on the video board, i will also add dont touch any pots on the DEF board apart from the three focus pots, i dont know if the XTRA has the blue defocus switch in that location near the pots like the PG PLAIN and PLUS, or if its in the menus like the XGs, but switch that off before focus adjustments on the blue, set all digital zone focus adjustments to their centered positions, set the center digital focus to -10, set the pots to their centered positions, then move the focus coils back or forward on the tube neck for best center focus.

Then center all the electronic astig controls, and set the astig magnets as per the instruction in the tech section.

From there, adjust the zone focus as required. The lenses should be focused with the full white screen and fully defocussed, adjust the lenses til you can see the phosphor grain through some close focussing binoculars, if you cant get those, you will be best off setting center focus by looking through the lenses, then using the H focus pattern to adjust lenses. Flip the blue defocus switch back on when you have the blue focus as sharp and as uniformly even as possible, if the blue electronic focus varies across the tube face you will have varying levels of blue output across the screen, as it gets brighter as you defocus it.

The PG XTRA is capable of some very sharp images, its factory fitted with the best AC lenses available, it has some of the best colour reproduction of any AC set, and certainly the convergence system blows away anything else apart from the XG.

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Barco CineMAX, 120" OZ Theatre Majestic 16:9 screen, H/K AVR 7.1...

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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Fri Sep 26, 2014 12:37 pm    Post subject: Reply with quote

I'll have to try 1080i... it seems like the general consensus is to not bother with 1080p. I am pretty happy with 720p right now

I took some of the advice and unplugged and plugged in the neck card wires to the video out board and that seemed to help with the white balance Issues. The set still is throwing up the bright red screen when I turn it on but I didn't try storing the settings like curt said to try yet.

How much better of an image will I get by adjusting the astig and focus magnets on the tube. I am a little scared sticking my hand in there while it is running. Isn't the high voltage stuff like 10s of kilovolts? Also the picture is pretty good already. Are my concerns with the high voltage warranted or is it generally pretty safe
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CasetheCorvetteman




Joined: 09 Nov 2008
Posts: 6319
Location: Australia


PostLink    Posted: Fri Sep 26, 2014 12:44 pm    Post subject: Reply with quote

Hard to say if its safe or not, but im not dead yet Wink

If astig and focus are set right, image quality will be rather exceptional.

Did you turn off the AKB in the menu?

_________________
Barco CineMAX, 120" OZ Theatre Majestic 16:9 screen, H/K AVR 7.1...

RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 5.1...
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Fri Sep 26, 2014 2:50 pm    Post subject: Reply with quote

I'm not sure but I think akb is off. I'll have to check

About the contrast and white balance I know not to run the set with contrast too high but I don't know what is too high. What do other pg owners have their contrast to?
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Fri Sep 26, 2014 3:47 pm    Post subject: Reply with quote

erniehart wrote:
About the contrast and white balance I know not to run the set with contrast too high but I don't know what is too high. What do other pg owners have their contrast to?


Comparing numbers in the menu makes no sense. They have no real meaning. A good pointer how hard you run your machine is to check how much the electron beam current is limited.

Check how big the difference between the "whiteness" of a small area of white on a black background versus a full screen white with your settings, the bigger the difference the harder(*) you push the machine.

(*): You may already noticed there are two little switches on the HV board, with those you can select from three modes: long life, normal, high bright. If your's is set to long life, you may see big difference between the two white areas, yet you are not overdriving your projector, but if you are in 'high bright' mode and the difference is big, you are over the top.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Fri Sep 26, 2014 4:04 pm    Post subject: Reply with quote

erniehart wrote:
How much better of an image will I get by adjusting the astig and focus magnets on the tube. I am a little scared sticking my hand in there while it is running. Isn't the high voltage stuff like 10s of kilovolts? Also the picture is pretty good already. Are my concerns with the high voltage warranted or is it generally pretty safe


The MG focus coil is in it's right place most probably, so you can go on with the electrical adjustments. You can decide if your astig magnets (aka. CPC magnets) are set right. Put up the dot fine pattern, set the contrast to 100% (don't worry about that for this little time) and check the shape of the dots in the CENTER of the picture when the center focus (magnetic) is at +100% and then at -100% If you got round blobs (ie. NOT triangle or ovals or anything else with a distinct flare) then the astig magnets are set well, otherwise not.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Fri Sep 26, 2014 4:13 pm    Post subject: Reply with quote

Where would I measure the current? Where is the hv board and the switches how do I know what is what?

I think i forgot to mention that the blue tube image shaking had been fixed as well
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Fri Sep 26, 2014 4:22 pm    Post subject: Reply with quote

erniehart wrote:
Where would I measure the current? Where is the hv board and the switches how do I know what is what?

I think i forgot to mention that the blue tube image shaking had been fixed as well


You don't have to measure current, it is just what is happening in reality, you just have to watch the two test patterns Wink

The HV board is in the far left corner (looking on a table top machine from the lenses), a vertically mounted board. There is a little chart drawn on that board to illustrate the switch combinations, and well, there are no other switches on that board, they are small push switches, you can't miss them. Smile

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Fri Sep 26, 2014 4:40 pm    Post subject: Reply with quote

I guess I'm not following you. It sounds like you want me to compare something between a small white patch and a big white patch but what am I comparing? The whiteness or brightness or something else
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Fri Sep 26, 2014 5:17 pm    Post subject: Reply with quote

erniehart wrote:
I guess I'm not following you. It sounds like you want me to compare something between a small white patch and a big white patch but what am I comparing? The whiteness or brightness or something else


Yes, you should compare how bright the small white pattern compared to the full white. (I intentionally stayed away from the word 'brightness' as it is meant usualy as a setting for the low levels)

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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CasetheCorvetteman




Joined: 09 Nov 2008
Posts: 6319
Location: Australia


PostLink    Posted: Fri Sep 26, 2014 9:25 pm    Post subject: Reply with quote

Set the brightness and contract to where you like them, but after you get them close, adjust the KELVIN settings so all three tubes are simular, all grey bars on a stepped grey bar pattern should be grey, and have no shade of any colour.
_________________
Barco CineMAX, 120" OZ Theatre Majestic 16:9 screen, H/K AVR 7.1...

RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 5.1...
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erniehart




Joined: 05 Jul 2010
Posts: 29



PostLink    Posted: Sun Sep 28, 2014 12:03 am    Post subject: Reply with quote

Thanks for all the help so far.

I am still having some issue with the red tube at start up tried saving or storing a kelvin and contrast setting and it didnt seem to change anything. any other possible solutions?

I also followed the procedure to check the astig and got good round blobs.

during setup there is one function that i am not exactly sure what it does. the phase cursor adjustment. what am i looking for with this setting. it seems as if that is making it somewhat difficult to get the best image but i dont know what it does or how to adjust it.
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CasetheCorvetteman




Joined: 09 Nov 2008
Posts: 6319
Location: Australia


PostLink    Posted: Sun Sep 28, 2014 3:04 am    Post subject: Reply with quote

You are meant to set PHASE correctly prior to ANY other adjustment for each source. Set it til the horizontal lines are perfectly even across the screen, and then align the hump with the middle of the screen ( what the aim is there is to get the convergence system perfectly aligned with the test patterns and centered within the screen so the adjustments are accurate )

Did you turn off AKB yet? Storing KELVIN has nothing to do with it, that will have stored whenever you stored anything else.

_________________
Barco CineMAX, 120" OZ Theatre Majestic 16:9 screen, H/K AVR 7.1...

RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 5.1...
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macgyver655




Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Sun Sep 28, 2014 3:43 am    Post subject: Reply with quote

erniehart wrote:


I am still having some issue with the red tube at start up tried saving or storing a kelvin and contrast setting and it didnt seem to change anything. any other possible solutions?



It is possible that your red problem is being caused by the red screen control having been tampered with previously. The red may be set to high and on startup the screen is red prior to the auto control kicking in.
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CasetheCorvetteman




Joined: 09 Nov 2008
Posts: 6319
Location: Australia


PostLink    Posted: Sun Sep 28, 2014 5:43 am    Post subject: Reply with quote

macgyver655 wrote:
erniehart wrote:


I am still having some issue with the red tube at start up tried saving or storing a kelvin and contrast setting and it didnt seem to change anything. any other possible solutions?



It is possible that your red problem is being caused by the red screen control having been tampered with previously. The red may be set to high and on startup the screen is red prior to the auto control kicking in.

I dont think there is one in in the XTRA Ron, i think the G2 pots are removed. Theyre present on the Plain and Plus PGs.

_________________
Barco CineMAX, 120" OZ Theatre Majestic 16:9 screen, H/K AVR 7.1...

RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 5.1...
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Sun Sep 28, 2014 6:59 am    Post subject: Reply with quote

CasetheCorvetteman wrote:
macgyver655 wrote:
erniehart wrote:


I am still having some issue with the red tube at start up tried saving or storing a kelvin and contrast setting and it didnt seem to change anything. any other possible solutions?



It is possible that your red problem is being caused by the red screen control having been tampered with previously. The red may be set to high and on startup the screen is red prior to the auto control kicking in.

I dont think there is one in in the XTRA Ron, i think the G2 pots are removed. Theyre present on the Plain and Plus PGs.


They are still there, but on a separate board, with opamps, and not on that splitter.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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View user's photo album (1 photos)
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