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LCD projector convergence HELP?!?!

Discussion in 'Electronic Repair' started by Patrick Young, Oct 30, 2005.

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  1. I have a number of broken Sony VPL-S900 LCD projectors.
    It appears on these the blue LCD panel is crap and
    literally burns out.

    Despite the part number being LCX031ALT2 on green
    and red and LCX031ALT1 on blue, I've moved an ALT2 panel
    into place from another unit.

    This is all good and well, works perfectly. The only
    problem is convergence.

    There is no adjustment in the screw holes and the mounting
    plates appear soldered to the prism assembly so I assume
    the convergence was done by aligning and soldering at
    the factory. Or is there another way? The alignment is
    out by around 4.5 pixels at the bottom and around 3
    at the top.

    Conspiricy theory: Sony knew the ALT1 was crap and also
    knew it would survive the warranty period and folk would
    come in for repairs later ....


    4x4 Hilux Auto Service Centre,
    BP 106 Timbuktu,
    Mali (West Africa)
    Tel: 292 91 52
    Specialising in turbo diesel and R290 aircon
  2. James Sweet

    James Sweet Guest

    The alignment may well be in the way the panels are made, hence the
    different part numbers. If you'd like to verify, try installing a
    different green panel and a red panel instead and see which one makes
    the convergence change. If the panels are indeed identical then the
    convergence is adjusted in software, if there's no service menu then
    you'd need a custom alignment rig. Given the cost of a new blue panel is
    probably prohibitive you haven't got much to loose, you may be able to
    file the holes a bit larger and adjust the panel that way to make it
  3. Did, as the green in Q had three or four pixels out. I'm now left with a
    ferpect picture, however the convergence is now out two ways. The part
    # is therefore not part of the alignment.
    I think I will do this. Setting up a test rig should not be
    too hard as the normal state of them appears off. With the spare
    parts/lense etc and a 250W mercury vapour lamp, should be able to
    do it to something usable for TV viewing.

    I've put in a call to see what the panels cost, if they are cheap I'll
    make an effort to repair as many as I can.

    Many thanks.


    4x4 Hilux Auto Service Centre,
    BP 106 Timbuktu,
    Mali (West Africa)
    Tel: 292 91 52
    Specialising in turbo diesel and R290 aircon
  4. James Sweet

    James Sweet Guest

    It's not? If changing to a different color panel changed the alignment
    then I suspect the panels *are* different.
  5. Sorry, I might not have been very clear there. I swapped a green _as
    well_ as the blue to make a comparison. The green was swapped with the
    same part # (ALT2) from the other projector, blue got red from the
    other one (ALT2 going into the ALT1 slot).

    There is more to it than just the part number. I suspect this has a lot
    to do with how the panel is cast into it's plastic housing.

    The plastic housing is then screwed in a non adjustable way on a
    plate that is soldered to the prism assembly at four points. Comparing
    panels, the soldering positioning varies (ie: there are larger tags on
    the prism than that of the plate the panel screws to), some of these
    solder points are on centre and some slightly off centre.

    I'm yet to work out the difference between the LCX031ALT1 and LCX031ALT2
    though. Of the 4 projectors I have, one ALT1 (blue) was totally burnt
    out in that had incinerated the colour filter, another the ALT1 was
    totally dead, however had not damaged anything. The remaining two still
    work, however are developing a blue smear in the picture. IIRC they are
    all much the same age.

    After finding the ALT2 panel works in blue possie, I'm left to the
    conclusion the ALT1 is the same, however perhaps a superceeded part #
    that had "issues". Interestingly, it is the one closer to the lamp,
    however would be surprised if it is different because it is warmer there
    and there are cooling issues, however that does not make sense to me.


    4x4 Hilux Auto Service Centre,
    BP 106 Timbuktu,
    Mali (West Africa)
    Tel: 292 91 52
    Specialising in turbo diesel and R290 aircon
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