• How To Adjust SMPTE on an Obsession IO PCB

    In most cases SMPTE should have been set correctly from the factory, but ETC did run into
    a few systems that needed adjustment in the field.  If the adjustments do not fix the problem
    use SMPTE Quickguide and verify the source.  The typical output will be +4 to +8 dBm, with
    a source impedance of 50 to 600 ohms.  This is roughly a 1.2 to 2 volt, peak-to-peak signal.
    If source is absolutely known good, then hardware problem exists.

    Verify that ECO1886 was installed.  You should see wire mod on back and cut trace.
    If not, ECO1886 will need to be performed.



    1. Verify that jumper J6 should have B and E on.
    2. P1 measurement. Center pin to outside pin=20Kohms Center pin is wiper
      Adjust P1 clockwise until you hear "click"
    3. P2 measurement Center pin to outside pin=0ohms Center pin is wiper
      Adjust P2 counter-clockwise for 20 turns, until you meter 0ohms
      Meter between center pin and outside pin on P2