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HD CRT Overscan\Flicker?

post #1 of 4
Thread Starter 
Okay, I'm new here so I hope I'm posting in the right place and I'm not quite sure if I used the appropriate terminology in the title, but here goes. Basically I have this old Sony WEGA Trinitron TV and it had always had really bad overscan and recently I've learned a lot and I actually went into the service menu and modified it enough so the entire picture shows up and is aligned properly. And boy was that ever a huge pain because messing with things like VPOS and VSIZ wasn't enough and so I had to find the settings by basically trial and error and now I've got as close to a perfect screen as I will ever get.

BUT I still have a few issues. One is that I still have overscan on 1080i. I tried modifying some other settings to try and fix it, but close to the bottom becomes distorted\curvy. Plus this isn't really my major concern because if I were to use it with my computer for instance, DirectX 10+ games don't seem to work with 1080i.

I'd be perfectly happy with 720p except for the fact that you can visibly see the flicker of the TV. As in say I have a white line going across the screen on an image, it doesn't seem like it's perfectly still, it's like when you pluck a string or rubber band. However this only visible on 720p. I don't notice it on 1080i and it's definitely not there on 480p. I haven't been able to find the settings in service mode to adjust this, although I did come across this setting MVLY under MID5 which if I set from 0 to 1, it fixes the flicker issue, except that it screws up the screen a bit and you can see it kind of shifting horizontally.

Any help is greatly appreciated, thank you!

Edit: I seemed to have found a solution to the flickering, but even if I write the change to the EEPROM, it keeps resetting back. I've found in the service menu this thing called HMSK under CXA2171 and is by default set to 1, but set to 0 my screen looks better, but it will not save. Any ideas?
Edited by Spirrwell - 6/30/13 at 10:32pm
post #2 of 4
You may have better luck in the CRT forum but have a look at this tread, it may or my not help you http://www.avsforum.com/t/531494/the-sony-service-codes-articles-comments-discoveries/0_100

Unfortunately times have moved on and there are very few posts dealing with CRTs as people who would be bothered with AVS have upgraded to new technology. The folks that are here who have been around since CRTs have not mess the them in a long time. I have done a couple and the advice I got for an XBR960 from someone who used to calibrated them was:

There's 2 pt WB, old fashioned color decoding with true color isolation, seperate RGB gamma adjustment (I often turned R 1 click higher to smooth out GS tracking), zone-type convergence, geometry, purity, and overscan (don't go overboard trying to reduce overscan; some OS controls will reduce resolution and beware of blank edges). A lot of that stuff I know when I see it, but trying to remember where they are and what they're called from memory is tough. Also seperate WB offsets for different input types/scan rates.
I tried not to mess with the magnet rings, but often I did take the back cover off and tweak spot magnets for color purity and geometry straightening.
Probably can get 40-45 fL light output if you push it up to the point of blooming, though it's possible to push it a bit harder. Use that contrast test pattern of mine to set contrast and watch for blooming.


Your best bet is to find the service manual and data mine the old archived posts that can be found with the advanced search feature in the CRT forum and here.
Good luck!
post #3 of 4
Quote:
Originally Posted by Spirrwell View Post

Okay, I'm new here so I hope I'm posting in the right place and I'm not quite sure if I used the appropriate terminology in the title, but here goes. Basically I have this old Sony WEGA Trinitron TV and it had always had really bad overscan and recently I've learned a lot and I actually went into the service menu and modified it enough so the entire picture shows up and is aligned properly. And boy was that ever a huge pain because messing with things like VPOS and VSIZ wasn't enough and so I had to find the settings by basically trial and error and now I've got as close to a perfect screen as I will ever get.

BUT I still have a few issues. One is that I still have overscan on 1080i. I tried modifying some other settings to try and fix it, but close to the bottom becomes distorted\curvy. Plus this isn't really my major concern because if I were to use it with my computer for instance, DirectX 10+ games don't seem to work with 1080i.

I'd be perfectly happy with 720p except for the fact that you can visibly see the flicker of the TV. As in say I have a white line going across the screen on an image, it doesn't seem like it's perfectly still, it's like when you pluck a string or rubber band. However this only visible on 720p. I don't notice it on 1080i and it's definitely not there on 480p. I haven't been able to find the settings in service mode to adjust this, although I did come across this setting MVLY under MID5 which if I set from 0 to 1, it fixes the flicker issue, except that it screws up the screen a bit and you can see it kind of shifting horizontally.

Any help is greatly appreciated, thank you!

Edit: I seemed to have found a solution to the flickering, but even if I write the change to the EEPROM, it keeps resetting back. I've found in the service menu this thing called HMSK under CXA2171 and is by default set to 1, but set to 0 my screen looks better, but it will not save. Any ideas?

Your flicker issue may derive from the difference between computer video timing and consumer electronics (CE) video timing. To a video card, 60 Hz is 60.00 Hz, while to CE gear such as Blu-Ray and DVD players, cable boxes, etc., 60 Hz is 59.9xx. Some displays such as our old Mitsubishi CRT RPTV, won't accept computer timing at all, while others may have an input that does, but is limited to 640X480 or another such VESA resolution. Before you go about messing around in the service menu, see if your vid card can be made to output standard CE video timing at 720p via the driver or a utility such as PowerStrip.

In addition, there is a difference between parts of the video signal in digital and analog video. Although the overall start-to-finish time of a video frame is roughly the same, some of the components of that signal are different lengths in analog and digital video, and that can confuse a display.
Edited by Rolls-Royce - 7/1/13 at 10:34am
post #4 of 4
Thread Starter 
Actually, I've been using a PS3 to fix my overscan and such. I resized an image to 1280x720 which was designed for projector screen alignment, and I was able to fix overscan with my PS3. But the flicker problem I do believe still exists while using my computer with it so I'll test that out. As for the thread that you posted airscapes I've actually passed by a few times, it was so long I was reluctant to look through it, but I will if you think it could help. Thank you.
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