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MItsubishi VS60609 No convergence correction

Discussion in 'Electronic Repair' started by Leonard Caillouet, Jan 23, 2005.

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  1. Are all of the clock and data lines clean on al the busses? Do all of the
    functions work other than convergence? Have you looked for coolant on the
    boards very very carefully?

  2. Hi all,

    I'm hoping someone has seen this.

    Mitsubishi 60" Projection
    Model: VS60609
    Chassis: VZ9+
    Cust complaint: Check over, pix distorted & curved

    This set has a uniformly bowed pix on all four sides, the customer
    convergence adjust has no effect and the convergence amp (STK393-110)
    stays stone cold. Replaced amp and confirmed plus and minus 24v, but
    with no change. Also, the plus and minus 9V, the 5V, and 3.3V to the
    convergence generator and op-amps check good.

    After further testing, it was discovered that the main system micro is
    sending a convergence mute (C_mute) signal to the convergence
    generator and convergence amp IC's. Apparently, the convergence
    correction is muted during power up and when switching input sources.

    I injected a DC power source in place of the C_mute output pin of the
    micro. As I slowly increased the voltage, a threshold was reached
    where the mute lines went high and convergence returned to normal. I
    could easily toggle the voltage back and forth and watch the
    convergence pop in and out. For some reason the micro is holding the
    voltage low. The microprocessor (100 pin flat pack) and eeprom was
    replaced, still with no change. At this point, I'm kinda running out
    of ideas. Anyone seen this?

    Alan Harriman
  3. Thanks for the reply. I've checked the convergence, main and tuner
    clock and data lines and they all look good at approx 5VPP. The other
    non convergence functions appear to work fine, ie Circuit Adjustment
    Mode items such as vert height, etc.

    I looked for coolant leakage, but did not see any. I'll look again
    perhaps more carefully. I'm almost tempted to put about a 4.7K pull up
    resistor from the C_mute line to a 5v source <g> Anyone have the tech
    support line for non-ASC servicers?

  4. Guest

    The system control is likely missing something it needs to see before
    it will turn on the convergence. Check all the inputs to the system
    control and the clock and data lines.
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