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Adjusting monitor focus: Sun/Sony GDM-5010 PT

Discussion in 'Sun Hardware' started by Steve, Aug 17, 2005.

  1. Steve

    Steve Guest

    Most Trinitron screens I've worked with have had the focus controls
    behind two obvious holes in the cabinet, towards the back on the left
    side. However, this screen doesn't seem to have those.

    Can anyone point me in the right direction?

    Please post here or email to steve_wechsler(at)yahoo.com

    Thanks,

    Steve
     
    Steve, Aug 17, 2005
    #1
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  2. Steve

    James Sweet Guest

    Take the cover off, they're still there on most monitors.
     
    James Sweet, Aug 18, 2005
    #2
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  3. Steve

    JANA Guest

    Open the back cover, and look on the flyback transformer. There may be two
    or three pots. One will most likely be the beam focus, and the other(s) will
    be the focus adjustment.

    In some sets, the focus control is on the CRT circuit board.

    Before touching anything, read carefully what the adjustment does. Use only
    a plastic or Teflon tip (non conducting) tool to adjust these pots. Using
    the fingers can be risky, if you are not used to this type of work. If you
    use a conductive type tool to do the adjustment, and you slip, there is a
    very good possibility to do circuit damage, as well as possibly get hurt.

    If the monitor or TV sets requires the focus to be touched up, this is a
    sign that either the CRT is going weak, or that there is something failing
    in the high voltage section.

    --

    JANA
    _____


    Most Trinitron screens I've worked with have had the focus controls
    behind two obvious holes in the cabinet, towards the back on the left
    side. However, this screen doesn't seem to have those.

    Can anyone point me in the right direction?

    Please post here or email to steve_wechsler(at)yahoo.com

    Thanks,

    Steve
     
    JANA, Aug 18, 2005
    #3
  4. Steve

    jdgill Guest

    Most newer Sony's use an external Digital Alignment System (DAS)
    connected to a computer to make these adjustments. (Expensive). You
    might try and trace out the circuit grom the screen (G2) pin on the CRT
    neck board. There should be a large value resistor in the circuit.
    Changing the value of this resistor will often change the screen
    voltage and brightness. You have to experiment a little to find a good
    value. I use an resistor box and start at the highest value and then go
    down until I find the best brightness. Then I solder a fixed resistor
    in the circuit.
    Hope this helps....
    John
     
    jdgill, Aug 18, 2005
    #4
  5. Steve

    James Sweet Guest

    You'd think someone would have hacked together a hobby version of the DAS,
    how hard could it be to do it with a cheap microcontroller? Of course you'd
    have to find access to a real DAS unit/software to analyze the protocol it
    uses.
     
    James Sweet, Aug 19, 2005
    #5
  6. Focus is adjusted using the traditional pots. Here's the extract from
    the n31s_fcs.stp file that drives DAS for the GDM-5010:

    BEGIN
    SCREEN "FOCUS ADJUSTMENT" 15 1 65 22
    message full_screen "Perform the focus adjustment:\
    a) adjust the [F2] focus pot for best vertical focus.\
    b) adjust the [F1] focus pot for best horizontal overall focus.\
    c) repeat [F1] and [F2] as there is some interaction."
    BUTTON CANCEL
    BUTTON OK
    END

    G2, however, is adjusted using DAS control.

    Mike.
     
    Remove _ for valid address, Aug 21, 2005
    #6
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