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LCD projector convergence HELP?!?!

P

Patrick Young

Jan 1, 1970
0
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
 
J

James Sweet

Jan 1, 1970
0
Patrick said:
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 ....


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
acceptable.
 
P

Patrick Young

Jan 1, 1970
0
James said:
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

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.
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
acceptable

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
 
J

James Sweet

Jan 1, 1970
0
Patrick said:
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.


It's not? If changing to a different color panel changed the alignment
then I suspect the panels *are* different.
 
P

Patrick Young

Jan 1, 1970
0
James said:
Patrick Young wrote:
It's not? If changing to a different color panel changed the alignment
then I suspect the panels *are* different.

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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