1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Barco 801S Picture Stability Problem

Discussion in 'Projectors, Screens & Video Processors' started by GlennR, Jul 11, 2004.

  1. GlennR

    GlennR
    Active Member

    Joined:
    Jan 22, 2004
    Messages:
    127
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Nottingham
    Ratings:
    +4
    I have a Barco 801s which I'm experiencing intermittent problems with the picture stability. The picture seems to try and collapse/flicker from the sides in. This is probably no coincidence that a noise coming from the direction of the EHT unit at the rear of the projector seems to be in sync with this fault. The noise coming from the EHT area fluctuates dependent on the brightness of the picture being projected

    Any recommendations or advice as to how the problem can be resolved?

    If the EHT transformer needs replacing - is this an easy precess and what price is a replacement part?

    Regards
    Glenn
     
  2. Roland @ B4

    Roland @ B4
    Active Member

    Joined:
    Apr 11, 2001
    Messages:
    2,238
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Reading.
    Ratings:
    +32
    Glenn
    Certainly what you describe is the EHT momentarily Collapsing.
    However I suspect this is probably more to do with a weakness in the powersupply. Faults in the EHT circuits tend to shut the machine down.

    How often does it do this?
    Does turning up the brightness cause it do do it more frequently?
    What frequncy are you running at? (press the text button)
    In the geometry menu what is the H size setting?
    Try running the projector with the H size reduced does that reduce the effect?
     
  3. GlennR

    GlennR
    Active Member

    Joined:
    Jan 22, 2004
    Messages:
    127
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Nottingham
    Ratings:
    +4
    Hi Roland,
    Thanks for the post.


    How often does it do this?

    Starts off when cold then after 30mins settles down a little but not completely. Instability increases with bright scenes.

    Does turning up the brightness cause it do do it more frequently?
    Yes, Brightness set at 70 and contast at 70. Anything lower than this makes the picture too dark.

    What frequncy are you running at? (press the text button)
    31Khz. I'm using a Iscan Pro fed from a DVD player. Problem is similar with S video feed at 15Khz fed directly from DVD.

    In the geometry menu what is the H size setting?
    Set at 50

    Try running the projector with the H size reduced does that reduce the effect?

    Reduced to 40 which had a slight effect but did not cure the problem completely. Again almost constant flicker which increases with change to bright scenes. (changed the V size to balance the reduction in H size)


    I've read a lot on this and other forums about poor solder joints on power supplies. Could this be another casualty?

    Regards
    Glenn
     
  4. cosmic023

    cosmic023
    Active Member

    Joined:
    Feb 15, 2003
    Messages:
    1,369
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    48
    Location:
    Somerset
    Ratings:
    +87
    Try a setting of Brightness=40 and Contrast=70, that's what i use and it looks good.

    Still waiting for my power supply to be mended.

    Good luck on getting your unit fixed.
     
  5. GlennR

    GlennR
    Active Member

    Joined:
    Jan 22, 2004
    Messages:
    127
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Nottingham
    Ratings:
    +4
    And the Plot Thickens......

    While testing various setup solutions, a bright flash (Arc) occured from inside the projector. Fans were still running but alas no sign of life from the tubes.

    On removing the cover and going through the power up procedure to try and locate the arcing, it was traced to come from a small board on top of what I have deduced to be the 'splitter'. (small board ref B4 714781-4?) The arcing comes from between the soldered connection with the black lead coming into the board and an adjacent soldered connection on the board. (I am assuming these should be seperate soldered joints?) (Please see attached image with the red arrow pointing to the arcing position).

    Can this be repaired? Or does the splitter need replacing?

    The LED on the EHT unit at the back of the projector is now illuminated RED. (Does this indicate an EHT holdown?)

    Am I right in assuming this could have been the root cause of the instability problem?

    What is the recomended course of action? Viable repair or Skip?

    Regards
    Glenn
     

    Attached Files:

  6. GlennR

    GlennR
    Active Member

    Joined:
    Jan 22, 2004
    Messages:
    127
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Nottingham
    Ratings:
    +4
    Problem Solved!

    Don't you just love a happy ending......

    After speaking with Henry at www.crtprojectors.co.uk, he agreed with my prognosis that the possible cause was probably the 'Splitter'. He duly despatced a used replacement which when fitted completely cured the stability problem.

    After a few hours extensive tweaking this evening the picture is rock solid. The noise from the Quad is also now non existent, obviousy the breakdown of the splitter was stressing the Quad.

    Highly delighted for such a small outlay.

    It's the people on this forum, and the Henrys of this world, who are only too willing to give advice and guidance which makes this HC experience even more enjoyable.

    Glenn

    :clap:
     

Share This Page

Loading...