Guys does this procedure seem correct?

I've translated it from the Version 1 service manual for my XG-751. I've replaced the Gain and Video out boards as the black level/AKB on B and G was misbehaving (fixed it, but white balance is a mess).

If you don't understand this stuff - leave it alone. You need a Cro and then you have to read the Japlish service manual a million times to start to figure it out.


Anyway, this is the (bad) English version:


XG Pot Adjustments.

1. Daughter board adjustment
· With Video crosshatch signal and 100% contrast, check TP701 and set Amplitude/Level VR-703 to 1.4v pp and Setup VR-812 to 0.1 vpp (see page 10-8)


2. Gain board Adjustment
· With Video crosshatch signal and 100% contrast, check R-TP7011, G-TP7012, B-TP7013 and set blanking/bias pots R-VR7002/G-VR7003/B-VR7004 so the blanking is the same as the pedestal level. (see page 10-9).
· Use TP7012 and set VR7008 Sub Cont to 0.7Vp-p.

3. Video out Adjustment (See page 10-10)
· Video crosshatch pattern
· Switch to Norm
· Video mode manual PAL
· B focus tracking ON
· AKB ON
· Br = 60%
· Cont = 100%
· Colour = 60%
· Sharpness = 50%
· Tint = 0%
· Warm up 20mins

3.1 Cathode Adjustment
· Adjust amplitude of Cathode TP7921 on Green Neckboard using VR7505 on Video Out board to 3.2vpp

3.2 Adjust BLACK BIAS to get 2.5v at R-TP7404 G-TP7504 B-TP7604

3.3 Tweak OSD colour of INFO screen using R-VR7401 and B-VR7601

3.4 Bring up all white test pattern, store AKB, then turn AKB off and store it again.

3.5 Check colour temp AKB On/Off is the same

3.6 Set BR=60%, Cont=75%, set Video Mode = Auto and Store.

3.7 Turn on AKB for all other signals, then turn off and store.


4. Neckboard Adjustments
· Video Crosshatch
· Watching R-TP7901 adjust R-VR7901 until pedestal is 1.4v above ground (see page 10-11)
· Watching G-TP7921 adjust G-VR7921 until pedestal is 1.4v above ground
· Watching B-TP7941 adjust B-VR7941 until pedestal is 1.4v above ground

5. Do Guy’s White balance procedure.

6. Drink Beer.


Any comments? Do you guys do this is the service manual order? Doug? Terry?


Thanks

Mark

I read it carefully and decided to go straight to option 6.

7. Repeat step 6 until convergence improves.

bump

I am bumping this bitch, anyone have any comments ;)

-Gary

I've done it now.

If all goes well it would take an hour. It took me 3 nights...

Problem 1: STAGE 2: Setting Sub Contrast to 0.7vpp - I was only getting ~0.3vpp on the scope. Tried a different scope and bingo, I was in the correct range. Must have been a sync issue....

Problem 2: STAGE 4: I don't know how to find the ground level on the scope, so setting a floating waveform 1.4v above it is tricky...I just left this bit alone, as my main goal was to set my new Gain and Video Out boards up.

Problem 3: In Guys White Balance I couldn't get the 50IRE window to disappear with brightness at zero. Exited out of all menus, reset brightness to 60, then zero again, went back into the Ref. White settings again and it worked fine....quirky, makes it lots of fun.

I had similar problems with the Xtra...the quirkiness makes it take twice as long.


But Gary, if you have a functioning projector, with stable brightness levels, the "back raster" is invisible as you raise brightness, etc, then just leave yours alone. My brightness level was changing unless AKB was enabled. I picked up NOS boards for $20 each so I wanted to use them - and of course they needed complete alignment.

Now my colour/brightness issues are solved, the XG is looking great :) And I learned how to set the pots and got more practice at the white balance.

Mark

Gary,
This is one procedure that I dont post about because it wont be translated / followed the same for or by everyone the same way or with the same test equipment knowing its personality.

The procedure from the service manual is correct but if you miss one little part of it AKB on or off, test switch position or not the right input, test pattern and level it wont be right and can down the projector and worse phosphor 'flash' the tubes.

Its 'see and do hands on' when your taking a multi purpose projector and using it for a specific HT projector.

Understanding what needs to be copied and what cant be copied from one input to another isnt going to happen. Seeing what isnt right or not normal cant happen unless you can actually see it real time. A weak or bad board, neck card, transcoder or even a cable issue is to much of a variance as well as the test probe or meter being used.

For the newbies reading this if you can take some advice from the guys that actually have to realign / calibrate and do it right we all advise 'Dont touch the pots' but few will believe it and do it anyway.

This in itself is a translation in the simplest form and in english (cant blame the service manual) and that isnt even translated or followed. Doug

What is a Cro?

Translated from Aussie Im not sure :D Doug

What is a Cro?


Cathode-Ray Oscilloscope

I guessed it could be cathod ray scope but is there any fixed panel scope?
This site has been overloaded or something. Hardly can log in.

Yes, most scopes these days are digital with LCD screens. Still referred to as a CRO, even though they technically aren't.

Caspian, if you don't have any issues with your XG, leave this alone...

Caspian, if you don't have any issues with your XG, leave this alone...

You are right no issues whatsoever. N on wood.
But still wouldn't mind to check it out. My unit still is in stock condition.
Right now I am swamped but perhaps in summer. I will ask questions and hoping both you and Doug would help. I have had some experience with scope but it has been years.

Doug, I still don't understand AKB ON/sotore/OFF procedure although I follow the prodecures and get good result. When should I do it? In what condition? What does XG get? What do procedure 3.5 and 3.7 mean? Does 3.7 mean each signal entry has its own AKB memory?

SYC

here's my deal guys, I know these things have to be screwy on mine for a few reasons, 1) is that I have streaking, pretty bad sometimes, especially red against a grey background(like DVDO scaler setup menus), I have had more than a few NEC XG guys tell me that streaking is made much worse (and is sometimes caused) by the pots being too hot

2) I have white crush that is not related to my sources, internal patterns have it and any source one input has it, you name it, my white balance is perfect following that great guide, my G2's are perfect, everything I can fix is good, my black levels are perfect, stable, and greyscale is spot on, my raster is invisible like Mark said, no problems other than white crush

my white crush looks like video signal blooming, not tube contrast related at all, take your contrast adjustment on your PC or scaler and crank it until your video signal blooms, this is my problem, it happens on any input, Svideo, component/RGB, Moome DVI card, any resolution any source, they all do it

I understand 100% Doug, no problems from me, I am a stupid tweak happy bitch and I won't even touch those pots, I would loved to get this fixed on my end from either another person or myself

-Gary

Doug, I still don't understand AKB ON/sotore/OFF procedure although I follow the prodecures and get good result. When should I do it? In what condition? What does XG get? What do procedure 3.5 and 3.7 mean? Does 3.7 mean each signal entry has its own AKB memory?

SYC

Yes, each signal entry has it's own AKB memory. Turn on ALL WHITE test pattern. Turn on AKB, store, turn off AKB, store, then exit test pattern - at least that's what I did.

The manual does not store with AKB on, which seems strange to me..

guys, Doug mentioned to me about the High Beam mode and such, those 2 switches on the HV board, I found very little info on those in the service manual other than what they do :confused:

the NEC manuals are total ass :mad:

-Gary

Gary,
Theres a small silk screen diagram on the HV board showing high beam and normal mode. Both should be in the out position. Doug

I think it adjusts the cathode current (or voltage) Gary.

thanks guys, I was golden/all normal, I searched some old posts and found Doug(who would have guessed) give a good explaination and the configuration of them ;)

I wonder if a guy like me who has his PJ on alot would benefit from the lower mode over normal ?

I am still interested to find where my clipping whites are happening, for example, 90 and 100 IRE patterns show very little difference between them when shown side by side, granted rarely is there ever that high whites in films, but when there is, it sucks :mad:

it's not bad clipping and is minor(I have seen alot worse) and most people would say I am out of my mind, but it is still there ;)

-Gary

thanks guys, I was golden/all normal, I searched some old posts and found Doug(who would have guessed) give a good explaination and the configuration of them ;)

I wonder if a guy like me who has his PJ on alot would benefit from the lower mode over normal ?

I am still interested to find where my clipping whites are happening, for example, 90 and 100 IRE patterns show very little difference between them when shown side by side, granted rarely is there ever that high whites in films, but when there is, it sucks :mad:

it's not bad clipping and is minor(I have seen alot worse) and most people would say I am out of my mind, but it is still there ;)

-Gary

I second to Mark. It needs a scope to calibrate the cathode current. The SM only tells to calibrate the G cathode current, but tells R & B only in a small section after tube replacement procedure. So if you follow Guy's procedure to calibrate white balance, you might ignore that small section.

SYC

SM is written in tech level language. If you have done this kind of work before it should be easy to follow. I found the Guy's G2 procedure very similar to SV's procedure in final analysis.

My raster is always visible a bit looking into lens but not on screen (for 5 secs) when pic muted.
The order is green with brightest and blue hardly visible. I think that is the way it should be. Getting the raster totally darken is not an option with my 1352.
While I am confident that my XG is calibrated near optimum I would like to hear what Doug and Mark would say about raster visibility in muted mode looking into the lens.

1) is that I have streaking, pretty bad sometimes, especially red against a grey background(like DVDO scaler setup menus), I have had more than a few NEC XG guys tell me that streaking is made much worse (and is sometimes caused) by the pots being too hotDON'T mess with the pots for streaking problems. I guarantee you'll cause more problems than you fix.

This "streaking" -- is it reds bleeding off to the right of a red area? I saw that on my XG when the signal was too hot, > 0.7V p-p. If you have an Extron or other processor that lets you adjust the output voltage, try backing it off a bit to see if that helps. Might even help your white crush.

Gary

The difference with Guys procedure and the service manual is the input being used. Guy uses RGB input 480P because it is closer to 1080I. The service manual uses the video input and specific NTSC test patterns and levels.

It would be hard to use different sources, DVD players and scalers to push the exact same level for everybody so you get these differences. We already know some devices crush blacks and some do the opposite depending how its set up like 'enhanced black' level on and off settings. The Toshiba HD DVD I believe is one of these that is pretty drastic from what I saw this last weekend but then again I had to sort this out to find out why. This is mainly what Im trying to point out being able to see what is going on real time then find out why.

Different transcoders and cables also change this so its kind of a crap shoot and working through it.

If you were a company selling a display device for multi use I dont think you would be using what ever you had at the time for setting reference or going through a rack of devices and any of input cards being used today for HDMI to RGB conversion.

You can go through the full service manual procedure including the pre boards and end up covering all inputs and have some sort of reference standard or you can follow Guys procedure to cover RGB and what most people are doing but this is also being affected by your exact signal chain DVD player and test disc. The 2.5V will be set though but it still will have differences.

What Mark just did was end up with a AKB setting thats stored that he could use on the other entries for a more accurate fine tune. This should let the back raster go to black as well as light up depending on the brightness level set. Some of this is personal preference / your actual hardware and what you like as well as the room itself and if it will go total black in black scenes and still not crush blacks or if you bring it up just enough to still maintain a black screen but give a better low end detail.

The gamma cards will change things just a bit also, hopefully for the better but another variance to think about.

Guys procedure does work for a given signal but you will need to try different settings for each persons tastes and actual signal chain. 2 IRE bar just on or totally off, 50 IRE bright gain vrs 40 etc. Doug

On bright gain 0 brightness I like to use the cross vertical ramp instead of the 50IRE box that leaves the edges of the box lit. For me its a more accurate reading.
Last... I have seen tubes at spec voltages that wont go black. Doug

Caspian, my rasters are 100% invisible with a 0 ire pattern or mute, I have have spent many untold hours and days getting my black levels perfect, the crushed whites elude me

Gary, I think you were one of the people I read talking about the streaking before ;), Yes the reds bleed off to the right youare correct, sadly though, any device I input does this, and on any input be it the RGBHV, Moome card DVI or svideo etc.

my scaler has no such adjustment either :(

-Gary

Caspian, my rasters are 100% invisible with a 0 ire pattern or mute, I have have spent many untold hours and days getting my black levels perfect, the crushed whites elude me

Hey Gary. With my current G2 I would be crushing black if I go based on zero back raster. May be I will get it next time when I redo G2. I am not sure it would be possible though. But other that it looks great with plenty of shadow d.

Displaying a gray ramp I can clearly see a different shades of gray in 90 &100. Although 100 ire look somewhat hot but I don't think it is crushing it. I run my contrast 40~50 on a 100" cheapo unity gain screen.

I had some one to do some measuring for me and I am getting 8.5 FTL will all white at 50 contrast d65 onto 100" wide. That is also what I get with my brand new Sony HS51a on the same screen well sort of 9 FTL in cinema mode. CRT is plenty bright.

Hey Gary. With my current G2 I would be crushing black if I go based on zero back raster. May be I will get it next time when I redo G2. I am not sure it would be possible though. But other that it looks great with plenty of shadow d.

Displaying a gray ramp I can clearly see a different shades of gray in 90 &100. Although 100 ire look somewhat hot but I don't think it is crushing it. I run my contrast 40~50 on a 100" cheapo unity gain screen.

I had some one to do some measuring for me and I am getting 8.5 FTL will all white at 50 contrast d65 onto 100" wide. That is also what I get with my brand new Sony HS51a on the same screen well sort of 9 FTL in cinema mode. CRT is plenty bright.

Caspian I do use a Gamma adjustment on my DVDO VP50, don't knock yourself ;)

anyone know a real good pattern to test high-level clipping of whites?

-Gary

Gary,
At your normal viewing levels what was the voltage variance between test and normal? (switch) Doug

May I guess?! 2.5x2=5.0V :D just kidding Gary.

Whatever happened with this Gary? I have white crush on my XG as well with the PS3, HD-A2, motorola cable box, and HDFury or RTC2200. I've done the W/B procedure by the way.

Also, this may be related. When I set grayscale (just by eye for now), I use the 80IRE and 30IRE windows and can set them to what I believe is D6500. However, at 100IRE and 20 IRE, the picture is too yellow, and at 70 to 40 IRE, the picture is too blue. B focus tracking is on. If this isn't related to the white crush, then forget I even said it, cause I'll have a colormeter by next week and will be able to post some data to go along with this.

Blue hump in midranges is normally caused by the blue saturating at higher IREs. The B focus tracking might not be doing enough. You may have to electrically defocus it to boost the blue output at high IREs. See this post (http://www.avsforum.com/avs-vb/showthread.php?p=10977935&&#post10977935) for a more thorough explanation.

Thanks Gary... that sounds like it will help with the grayscale as I will be able to turn B drive down a bit which will in turn bring up the blue in the lower IRE to reduce the hump. I just ordered a Eye-One LT so I don't have to rely too much on my eyes anymore.


As far as the white crush, could it have anything to do with this (http://www.avsforum.com/avs-vb/showthread.php?t=872980)?

I think I have the symptoms he listed in the "common case section". I have a faint white line on the right side of the screen during dark scenes and I have the stripes he describes, although mine move with the image.

I really think I need to have all of the pots calibrated and am trying to get in contact with someone, although I haven't been too successful so far.