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Samsung TXN2798HF Geometry

1209 Views 8 Replies 4 Participants Last post by  Irishman5
Does anyone know if there is an adjustment in the TXN2798HF for top horizontal bow? I have been through the service menus and see no way to correct this. The image is fine in the middle and bottom quadrants. Any thoughts?
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I can't comment on geometry and all that fun stuff, but I can tell you that after reading through many sites on this TV, I found some settings that are awesome.

I first got this TV about 2 months ago and I am new to this home theater stuff, but I'm already an addict. The guys on this site are

F#@%ing GREAT. My TV went from looking very pixelated and crapy to looking excellent. I just got the KENWOOD 506 home theater system and it rocks. Granted, I have never had surround sound before but for $300 bucks this setup rips. I also have an X BOX and a samsung DVD player hooked up. FYI - X BOX looks ridiculous on this setup!!!!!! ESPN football: WOW.

Anyway, I got my TV to look great by going into the service menu. ******Don't do this unless you remember to write down everything and anything you change********

GET the Digital Video Essentials (DVE) calibration DVD, to set all the regular menu settings such as contrast, brightness, color, etc.

I promise you that your TV will rock after these changes.

PS: Change the GAMMA setting to 1.
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There was an older post that described the different settings and values, I cannot find the original post, but I did save a copy of on my hard drive.. I'm not sure if this was intended for the 27" or the 30" widescreen, but it still should be of help.

The author is unknown but his hard work is appreciated..

"PT II - Sorry for the double posts, but since I went to all the work to write this stuff down when I was doing it, thought I should be thorough in case it helps anyone else, and perhaps saves others some time/effort.

As you probably know, I don't think we can provide any "exact defacto" values to correct Overscan/Geometry or service menu Color adjustments, as I believe there will be variations in every tube, so every set will need to be "calibrated" differently where geometry/overscan and RGB Drive/Cutoff Color adjustments are concerned. Same thing would probably be true for the CR/CB offset and 480p/1080i CR/CB/S-tint/S-color adjustments in Video Adjust 3 as noted above, depending upon the output of the 1080i/480p source "device".

But, FWIW, Follows is what worked best for me for Geometry/color, as well as description of what everything does -- In other words, just using the values I'm using isn't going to work, unless by some twist of fate your default values and actual geometry on screen exactly match what I have, which I'd think is very, very, very unlikely.

Note: Had a couple of problems with the values I originally posted concerning Color, proper aspect ratio for 1080i, as well as V-Linearity "issues" with Fast Camera pans/etc, I 've updated this Post and post above on 1/13/04 with the New(should be pretty much final) values.

Note that it is Necessary to adjust these parameters with a proper test pattern, at least for the "Deflection" menu. If you adjust some of the values, especially beyond a few 00+ or -00 you Will need to properly set and readjust the "Linearity" settings, which again, will require a proper test pattern and probably some measuring of squares in a crosshatch pattern/etc. What I did was, set geometry with a proper test pattern in "Deflection" menu(controls geometry for 480i), and then made minor adjustments to necessary values in 480p+1080i offset menus(you can only adjust these when your feeding TV a 480p or 1080i source respectively). Another hopefully helpful hint: You also have to exit and reenter service mode to set geometry for 480i and /1080i/480p menus"individually", although(updated), If you're using Component input, you can change the output on your STB between 480p/1080i and adjust those individual menus while in Service mode.

Basically, on my set, besides the Bow problem I mentioned in last post, Geometry wise, the other problem was too much overscan. Out of the Box, one of the ID logos of my local digital station, which is allways put on top of screen was 1/2 cut off. While I was able to improve the overscan quite a bit, it was still necessary to compromise(IF I wasn't using this set for 480i, especially analog sources, I wouldn't have had to compromise) and I lost a little more "screen area" than I wanted to in 1080i and 480i. Also, the Geometry you get(especially noticable when watching 4x3 as 4x3) is effected somewhat by Contrast/Brightness settings, so I found it useful to "tweak" some things(esp. the Corners+H parabola) by going in and out of Service mode and "testing it", and making necessary very slight adjustments even though it didn't necessarily look "just right" when in the service menu via using the "torch mode" Dynamic Picture mode settings.

My Changes first, Default values in parentheses :


Deflection Menu:

V AMP: 29 - (33) - Vertical Size

V Shift: 21 (32) - Affects where image is located, vertically, on screen - Doesn't effect other geometry settings to any significant degree.

H EW: 24 - (28) - Horizontal Width

H Shift: 28 (28) - Horizontal position on screen. Note that you often can't just set this to exactly center an image, as many sources(such as from a DTV station) will be shifted slightly to the Left -- Another reason to use a proper test pattern ...

V linearity: 4 (4) - Controls ratio of width to height within picture area for the entire portion of screen. Use a cross hatch pattern, and get it so that the "boxes" are the same distance apart vertically anywhere on the screen, and along with V-shift values, make sure the Center Box is really in the center of screen.

Upper Linearity: 9 (7) - "subset" of V linearity(see crosshatch pattern note above) Controls ratio of width to height within picture area for the Top portion of screen. (Note: Changing V Posistion will especially effect the necessary value)

Lower Linearity: 5 (7) - "subset" of V linearity control, this Controls ratio of width to height within picture area for the Bottom portion of screen. (Note: Changing V Posistion will especially effect the necessary value)

V SC: 3 (3) - Vertical Scaling - Basically, effects Vertical size

H Parabola: 21 (21) - Convex Bow in/out on both L+R sides of screen, with middle of bow "aiming" towards the middle on both sides.

Upper Corner: 34 (34) - "pulls" in/out the upper corners.

Lower Corner: 30 (28) - "pulls" in/out the lower corners.

H Trapezium: 56 (31) - Widens top/narrows bottom, or narrows bottom/widens top : very much affected by the "V Position" setting.

Bow: 32 (29) - Convex Bow in out for L/R side of screen, with middle of bow pointing to the right.

Angle: 33 (30) - Higher value pull top(and rest of image except the bottom) to right, lower values pull it to the left.

V Position: 46 (32) - Vertical Position of image on screen -- DOES affect other geometry settings to a significant degree - especially H Trapezium - As noted above, on my set, setting this to a higher value allowed me to better correct for a bow issue with the other settings, which seemingly could not be addressed otherwise in a manner which was an actual improvement.

CXA Left BLK: 36 (30) - Allows you to cover up a portion of left edge of image.

CXA Right BLK: 35 (37) - allows you to cover up a portion of right edge of image.


Menu 480p Offset: For the most part, this uses the values from "deflection" menu"(which is for 480i sources) and allows you to adjust them "slightly" for 480p -- I believe the last 2 values don't even use the values from Deflection menu, these I've noted with a *)

V Amp: -5 (3)

V Shift: -3 (-1)

H EW: -6 (2)

H Shift: 4 (4)

V Linearity: 0 (0)

Upper Linearity: 0 (0)

Lower Linearity: 0 (0)

V SC: 0 (0)

H Parabola: 1 (1)

Upper Corner: 2 (2)

Lower Corner: 0 (2)

H Trapezium: 0 (0)

Bow: 0 (0)

Angle: 0 (0)

V Position: 0 (0)

CXA Left BLK: 42 * (28)

CXA Right BLK 16 * (36)

1080i Offset: Works just like 480p offset menu, which I assume is the case for the DVI Offset menus, which I'm not using since this set doesn't have DVI input available on back of set.

V Amp: -11 (-13)

V shift: -5 (-3)

H EW: 7 (5)

H shift: -3 (-3)

V Linearity: 0 (0)

Upper Linearity: 0 (0)

Lower Linearity: 0 (0)

V SC: 0

H Parabola: 0

Upper Corner: 0 (2)

Lower Corner: 0 (2)

H Trapezium: -0 (0)

Bow: (0)

Angle: 1 (0)

V Position: 0

CXA Left BLK: 46 (50)

CXA Right BLK: 30 (27)

Video Adjust1 Menu : Color setting Changes :

Of course, Color tone(which can't be set in Service menu) effects the color "balance" as well, so I often found it useful to go out of service mode, and check results with my "custom" PQ settings.

I thought the Colors "out of the box" looked a bit unnatural, no matter how I adjusted the "Tint" in the "custom" user menu --- Especially Reds looked unnatural, and Setting COL Axis to 1 to correct for Red Push didn't fix it for me completely ... Anyhow, in the case of this particular set, with the "warm1" Color Temp setting, The below changes now seem to work quite well. As noted in last post, Changing value for "sub tint" was very necessary+made the slight adjustment needed to the Drive values much easier. Anyhow, I had the most difficulty getting Cyan to not be Blue, or, with Too much Red+Cyan -- Also, at first had difficultly with having too much green when I first started adjusting these settings --- I was surprised that the values ended up being as close as they were to the original values for what seems to be the best, most natural looking result.

R cutoff: 22 (Original value 22)

G Cutoff: 24 (Orig Value 24)

B Cutoff: 24 (Orig vaue 24)

R Drive: 24 (Orig value 24)

G Drive: 27 (Orig value 24)

B Drive: 24 (orig value 27)


Also ... again, a disclaimer .. Enter the Service Menu and make changes at your "own risk" and DEFINITELY write down the Default settings for YOUR set before you make Any changes, so you can return to default values if necessary.

One final note on this set ... I really was a bit surprised that this stuff(and so much stuff) really needed to be changed on this set ... I have to wonder HOW they are setting these things at the factory, because, out of the box, I was most definitely NOT pleased with the "picture". The Default SVM setting was simply intolerable, Colors looked unnatural(but I probably could have lived with that if there had been no other problems) and On the "bow problem" this particular set was showing with the factory defaults, for example, it was so bad that on a U.S. Weather map, the Tip of Alaska was pointing to the South of Hawaii! If I wouldn't have been able to correct these issues in the Service menu, the set would have went back. Things are so, so much better now -- Everything looks really good, although, I still can't say HD looks quite as sharp and detailed as it does on my other HD display (RCA F38310). I have a feeling though the "sharpness" issue might in part be due to an issue with the Component out on my STB.

Anyhow, If "average joe" got the HD pic I did when I first turned the thing on, he'd likely be wondering what all the fuss over HD is all about! I do understand now why using a ISF calibrator can seem fairly expensive(as well as a good idea), I can honestly say I put $200(or more) of "work" into this set."
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Here's the updated version :


I have since edited the post which breakstuff posted above, although I didn't change my geometry settings since then(again, what you need will differ+MAKE SURE you know what you're doing as well as writing down the default values before changing anything in service menu) ...

There is also lots of other great info on the TXN2668(much of which I believe applies to most other TXN sets) in above referenced thread, some of which we discuss the geometry settings in more detail .... So I would suggest you check out all the posts in the above referenced thread ...

Also I can't recall which post in the thread was involved, but I'm pretty sure we did talk about Horizontal Bow at one point -- Without going into detail here, There isn't a "direct" adjustment for H-Bow, but "other settings" can mininize it ....

Good luck,
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Great information Nitewatchman-

All your hard work helped me greatly improve the picture quality of my TXN 3071. :)
Thanks, its great to hear it was useful.

I should also mention other unknown authors from various threads and sources deserve much of the credit, especially for the non-geometry service menu "tweaks"(SVM, DPIC level/etc/etc/ settings).

Isn't AVSforum great :)

Thanks for the GREAT info on the service menu tweaks. I used your settings (video) for my TXN2798HF 27" 4x3 Tantus HDTV and the results have been great. I was wondering though about the geometry settings that you have, can I ue these on my TV. I have digital video essentials, can I use this for this purpose? Some stupid Q's: What is Scan velocity modulation, overscan, and bow and how can I tell if I have these issues. I would really appreciate your feedback, as I am now obssessed with this home theater stuff. I had no idea that TV's could be tweaked to look so good!!!

Thanks again.

NO you can't use the same settings I have+expect to correct any geometry based issues on your set. EVERY tube will require different geometry(deflection) settings. Even if you were using the same model set that I am, your settings would likely need to be different.

Yes, you can use the test patterns from Calibrations disks like avia or Video Digital essentials for Geometry/Overscan issues, in fact you need the test patterns to do it.

You can find plenty of info on overscan, SVM(scanning velocity modulation) and geometry issues(such as bows) if you search for those terms on AVS, or with you're favorite search engine. This is also a good resource for information on CRT(picture tubes) issues :


A good, quick explanation of Overscan in the document here:


Here's a decent explanation of SVM :


Here's a more thorough explanation of Overscan - with Pics :


I'm afraid at this point I can't think of anything else to add to my comments as posted in the thread referenced above.
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Thanks for the feedback. Please let me know if you get ahold of a 4x3 txn to test geometry.

Thank you so much
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