CRT and Resolutions

Discussion in 'Projectors, Screens & Video Processors' started by KarlRobinson, Oct 9, 2002.

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  1. KarlRobinson

    KarlRobinson
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    If you have a 16 x 9 screen with a CRT and are planning to use a HTPC is a 16 x 9 resolution the right way to go or a 4 x 3 and just stretch it?

    I could use 1024 x 768 or 1280 x 720 or variants.
     
  2. Roland @ B4

    Roland @ B4
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    Use the 1280 x720 for an 8" EMF projector Barco Cine 8, 808, Sony G70 Electrohome 8500.

    Slightly lower for 7" electostatic Barco cine 7,708, Sony D50 etc.

    Probably about 1024 x 576 would be better.

    By using these setting the desktop features will remain in aspect ratio. DVD should always be set to fill the screen
     
  3. Boris Blank

    Boris Blank
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    Talking of resolutions, I run 1280x768 @71.928 on my BG801s, it looks great but I'd love to try more standard DVD resolutions 1080x720 etc, but..... each time I input a new resolution, the desktop ends up with a slight shake!

    I've tried new drivers etc but the problem remains. I had originally thought that the video card was the problem but I'm beginning to suspect its the projector, even lo-res stuff shakes ever so slightly!

    Like I said, 1280x768 is rock solid but I'd like to try something else (out of curiosity if nothing else - any advice?

    Also, slightly OT, my convergence never seems to stick from the previous session, its not far off, 3, maybe 2 millimetres and its a 10 second job to change it but next time I power up the crt its still not properly converged after an hour or so warm-up. New convergence board required perhaps - got an indication of cost so I can decide to live with it or cough up to get rid of it?
    regards,
    Paul
     
  4. Paul D

    Paul D
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    Hi Paul

    The slight wobble can be helped by running your VGA card with negative sync. Port 3 is worse for it, port4/5 should better etc.

    The convergence drifting can be caused by a couple of other things excluding an actual fault with the convergence board.

    A stable room temperature a must, as the big CRT lenses need time to warm through. Anything up to 3 hours from a very cold room!. So try to keep the room at the same temp.

    The next tip is to set aside a convergence day. :)

    Give the projector a minimum of three hours to warm through, showing a running program/film.

    Then do a nutter convergence on each memory block, including a electronic focus if your machine allows it.
    I also did a lense focus as well since they were at full temp etc.

    I too used to converge on a daily basis, but since i did the above a have not needed to touch it at all in over two months.

    The reward is a faster optimum film start time and a superbly focused and converged "highly" detailed image.

    [​IMG]

    Above pic from Barcodata 808s/Quadscan Elite/Pioneer737
     
  5. Roland @ B4

    Roland @ B4
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    I'd say you were pushing this projector at this resolution. bring it down to 800x600. That sholud give it less to do and the convergence will become more stable.
     
  6. Boris Blank

    Boris Blank
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    Roland/Paul,

    (Made a longer more detailed reply but lost it - this is the 2nd version).

    Thanks for your replies.

    Yes, convergence nutter day it is then - I had been putting this off as I couldn't be bothered but from your comments, that would pretty much be in line with whats happening and the best way to resolve it! Temperature control is lacking to say the least - I'll up it and make it more stable (currently its off most of the time).

    Port 3 is exactly what I'm using - I'll get one of Mike Parkers modded Radeon cards and go back to Port 5 (been thinking about that for a few weeks anyway).

    800x600! I've not tried that, primarily because "if my pj can do 1600x1400 then thats what I'm using" - wrong attitude. I'll try 800x600 and seriously give it a go.

    Great advice guys, many thanks.
    Regards,
    Paul
     
  7. Roland @ B4

    Roland @ B4
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    Under the service mode there is a set to midposition for the convergence. When you do this the red and blue centre line must be exactly aligned or you will never get it stable.

    Do a search for the thing I wrote about this "brass headed pot should bring it up.
     
  8. Boris Blank

    Boris Blank
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    Hi Roland,
    I'll do this as part of the "nutter convergence". I'll do a complete 100% setup again (wipe all blocks and install from scratch, etc). Its really only in the past few couple of months that I have got back into HTPC and the current setup for the pj is primarily geared towards an external DVD player & scaler so its time to fine tune it purely for HTPC alone and do some general "housekeeping" on the pj.

    All good fun though, I quite enjoy tinkering!
    Regards,
    paul
     
  9. Boris Blank

    Boris Blank
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    Nutter convergence completed and the verdict is......no change:mad:

    No matter what, the convergence is always off by the same amount when powering up when its been off for a few hours - whats the cost of a replacement convergence board for a BG801s?
    regards,
    Apul
     
  10. Roland @ B4

    Roland @ B4
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    I don't think you will find this is the Conv board issue. New price is about £2500 by the way.So lets make sure. Few more checks for you.
    Is the misaliagnment just in one area?
    or the whole screen (ie does the centre raster shift fix it)
    Does it effect blue and red.

    If it is just the raster shift is the line out horzontally or Vertically?Now that you have done the Midposition pots it should be possible to run the projector without the Convergence board in switch the PJ off first obviously and you will probably find the infrared remote won't work.
     
  11. Boris Blank

    Boris Blank
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    Hi Roland,
    many thanks for replying.

    The misalignment is basically across the whole screen (from memory - looks worse in the middle, less so on the outer edges but I did notice that when correcting the middle the outer edges more or less snapped into place but I used the convergence screen rather than the raster shift).

    Affects the blue only. It drops downwards by about a centimetre. Red is initially out as well but moves quickly into place after about 30mins.

    I'll pull the board tonight and see what happens.

    £2500, blimey thats a lot - I think we all forget how much CRTs really cost, its only when you start looking at spares that the true value starts to raise its head!

    Regards,
    Paul
     
  12. Roland @ B4

    Roland @ B4
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    Check to see that all four bolts that change the lens toe in are secure. that can very easily cause what you are seeing.
     
  13. Boris Blank

    Boris Blank
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    Thanks Roland, I'm going to have a thorough look at this at the weekend. I started to have a look but keep getting distracted so I'll have a look in slow time.
    Cheers,
    Paul
     
  14. Boris Blank

    Boris Blank
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    Blimey! These Barco boys must be built like gorillas! Either that or I'm being dim (maybe both! :D ).

    I just tried to pull the convergence board but it ain't budging - theres a big black lever in behind the tubes that I think is the release catch for the board but I'm bu**ered if I can get it to do anything! The board doesn't budge more than a couple of millimetres.

    Am I missing something here? (apart from a few screws!)
    Paul
     
  15. Roland @ B4

    Roland @ B4
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    Open the case and look between the rear of the tubes you will see two 6-9" long silver knobs which are totally over engineered for their pupose. The hold the heat sink in contact. loosen them off (I don't think they come right out).
    The black lever is the eject thingy use it to push the board forwards. It doesn't need to come right out just away from its contacts by about an inch.

    But you are quite right about the frame of the women who put Barco projectors together.
     
  16. Boris Blank

    Boris Blank
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    LOL - very good!

    Thanks Roland, I had been under the mistaken impression that the heat sink/rods didn't actually go all the way through to the convergence board so looked at them but didn't do anything with them - duh!
    Paul
     
  17. Boris Blank

    Boris Blank
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    Well, I converged the pj, popped the convergence boad and switched it back on.

    What I expected to see was a fairly converged picture but no, the convergence was all over the place - arrgggggh.

    Ok, I'll start again from scratch - must be that I've converged using the electronics at some point when in fact I should have used the mechanics (which I thought I had but obviously not!). Doesn't take long so another nutter convergence coming up!

    Just as well I don't have AOTC or LOTR yet otherwise I'd be real hacked off.
     
  18. Roland @ B4

    Roland @ B4
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    Woh Paul it should be you are just looking at the centre.

    Pulling the convergence board out will,..... er make the convergence go scatty. What I'm trying to establish here if the drift is caused by North/South East/west movement.

    Take a note of where the centre cross is use a video if it helps. see if you get the same level of movement with the Conv board out.
     
  19. Boris Blank

    Boris Blank
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    Up bright and early!

    Ok I got ya I just jumped ahead a bit too far! I had a panic when I saw that the left and right sides of the screen were way out. I understand now though. I'm going to have to re-do the whole thing again anyway but I have a deeper understanding of what I'm doing and how to do it - and now how to check it to make sure its right (or see whats up with the drift).

    Its pretty clear (or it was until I forgot about it!) that getting a good mechanical setup is crucial - I suspect whats happening here is that I have an excellent electronic setup but (possibly) a poor mechanical setup (lots of fiddling with the pj has maybe thrown things a bit) which is causing the drift.

    However, having had a nutter convergence last week with no perceived change in the drift problem I'm a bit puzzled by what may be causing it so I'm happy to go back to basics and start again and this time CAREFULLY(!) track the drift and do the convergence board removal trick and see whats going on.

    This is actually fun but a bit frustrating - between this and setting colour and focus, I think my pj has had more time tweaking than movie watching! But when its running, it looks absolutely gorgeous:)

    On a different note, having pulled out most of the boards at one time or another, do Barco boards have a smaller component count these days? I mean the convergence board which dates from 1994 is HUGE, surely the chip count these days must be vastly reduced and therefore the boards are a lot smaller in the newer models?
    Paul
     
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