Help with LP735 projector...

[mc]

Bought this one second hand ..not 100% ..

has yellowish spot in middle of the screen or darkish grey on a blue
screen .. I assume this is due to the lamp ..has done 1590hrs of the
2050 ..
That one is not that noticable as the shadowing purple-red image of any
black line or writing(text) on the screen..

ie when the menu is up ..you can see all the proper image on there
...but any blakish type lines have like a shadow of that black line or
writing to the left of it 3-4cm on a large screen... I've tried every
adjustment but no luck ..it is as if the red side of projector is
producing double images ..as all the white made images are ok ..so the
colours are mixing properly

has anyone stuck this on these projectors and how hard or easy is it to
fix..

I did open the unit ..but nothing that I can see that has any
adjustments etc that can be made.

the yellowing I suppose in the centre of the screen could be a dying
lamp? I've never seen that before ..or is it from something else ..

If some one is interested to purchase it like that I will consider it
...But I'd rather get it going as it is good watching movies with it ..as
it can do 1200x1000 mode using a pc..

TNX ahead

[mc]

bit of specs on his

http://www.projectorcentral.com/InFocus-LP735.htm


mc wrote:

> Bought this one second hand ..not 100% ..
>
> has yellowish spot in middle of the screen or darkish grey on a blue
> screen .. I assume this is due to the lamp ..has done 1590hrs of the
> 2050 ..
> That one is not that noticable as the shadowing purple-red image of any
> black line or writing(text) on the screen..
>
> ie when the menu is up ..you can see all the proper image on there
> ..but any blakish type lines have like a shadow of that black line or
> writing to the left of it 3-4cm on a large screen... I've tried every
> adjustment but no luck ..it is as if the red side of projector is
> producing double images ..as all the white made images are ok ..so the
> colours are mixing properly
>
> has anyone stuck this on these projectors and how hard or easy is it to
> fix..
>
> I did open the unit ..but nothing that I can see that has any
> adjustments etc that can be made.
>
> the yellowing I suppose in the centre of the screen could be a dying
> lamp? I've never seen that before ..or is it from something else ..
>
> If some one is interested to purchase it like that I will consider it
> ..But I'd rather get it going as it is good watching movies with it ..as
> it can do 1200x1000 mode using a pc..
>
> TNX ahead
>

[mc]

I've found so far on the web (in one of reviews) that yellowing may be
due to underperformance of one of the LCD screens (probably blue)..there
must be 3 in the unit.. in that case I'd be unlikely to get a
replacement ..so if someone has a same projector and needs parts ..make
a reasonably good offer and I will ship it to ya.. I'd be looking for
$500ono

mc wrote:

> bit of specs on his
>
> http://www.projectorcentral.com/InFocus-LP735.htm
>
>
> mc wrote:
>
>> Bought this one second hand ..not 100% ..
>>
>> has yellowish spot in middle of the screen or darkish grey on a blue
>> screen .. I assume this is due to the lamp ..has done 1590hrs of the
>> 2050 ..
>> That one is not that noticable as the shadowing purple-red image of
>> any black line or writing(text) on the screen..
>>
>> ie when the menu is up ..you can see all the proper image on there
>> ..but any blakish type lines have like a shadow of that black line or
>> writing to the left of it 3-4cm on a large screen... I've tried every
>> adjustment but no luck ..it is as if the red side of projector is
>> producing double images ..as all the white made images are ok ..so the
>> colours are mixing properly
>>
>> has anyone stuck this on these projectors and how hard or easy is it
>> to fix..
>>
>> I did open the unit ..but nothing that I can see that has any
>> adjustments etc that can be made.
>>
>> the yellowing I suppose in the centre of the screen could be a dying
>> lamp? I've never seen that before ..or is it from something else ..
>>
>> If some one is interested to purchase it like that I will consider it
>> ..But I'd rather get it going as it is good watching movies with it
>> ..as it can do 1200x1000 mode using a pc..
>>
>> TNX ahead
>>
>

[Brian Goldsmith]

"mc" wrote



Message1) Bought this one second hand ..not 100% ..------

Message 2) in that case I'd be unlikely to get a
replacement ..so if someone has a same projector and needs parts ..make
a reasonably good offer and I will ship it to ya.. I'd be looking for
$500ono

**** Poor bastard,from hope to hell in three hours!!! :-)

Good luck!


Brian Goldsmith.

[mc]

that was only desperation since I did not get any replies.... :) was a
good trip but ..glad to see some reads the messages @ least.. but
really if someone has usefull info appreciated .. I am sure the
shadowing effect is fixable ..not sure about the yellow spot ..watched a
movie last night ..it did not bother me that much as the red shadows
(of black lines)






Brian Goldsmith wrote:

> "mc" wrote
>
>
>
> Message1) Bought this one second hand ..not 100% ..------
>
> Message 2) in that case I'd be unlikely to get a
> replacement ..so if someone has a same projector and needs parts ..make
> a reasonably good offer and I will ship it to ya.. I'd be looking for
> $500ono
>
> **** Poor bastard,from hope to hell in three hours!!! :-)
>
> Good luck!
>
>
> Brian Goldsmith.
>
>
>

[Dave T.]

LCD projectors are disposable, apart from the lamp, lesson to be learned
although a hard one, but you'll know in future :)

"mc" <phmc@cc.newcastle.edu.au> wrote in message
news:c3agdm$14s$1@seagoon.newcastle.edu.au...
> Bought this one second hand ..not 100% ..
>
> has yellowish spot in middle of the screen or darkish grey on a blue
> screen .. I assume this is due to the lamp ..has done 1590hrs of the
> 2050 ..
> That one is not that noticable as the shadowing purple-red image of any
> black line or writing(text) on the screen..
>
> ie when the menu is up ..you can see all the proper image on there
> ..but any blakish type lines have like a shadow of that black line or
> writing to the left of it 3-4cm on a large screen... I've tried every
> adjustment but no luck ..it is as if the red side of projector is
> producing double images ..as all the white made images are ok ..so the
> colours are mixing properly
>
> has anyone stuck this on these projectors and how hard or easy is it to
> fix..
>
> I did open the unit ..but nothing that I can see that has any
> adjustments etc that can be made.
>
> the yellowing I suppose in the centre of the screen could be a dying
> lamp? I've never seen that before ..or is it from something else ..
>
> If some one is interested to purchase it like that I will consider it
> ..But I'd rather get it going as it is good watching movies with it ..as
> it can do 1200x1000 mode using a pc..
>
> TNX ahead
>

[mc]

Hi managed to open the beasty up and pulled it to bits ..found a piece
of glass or a filter that is is front of the blue LCD ..it is piece of
glass and another bit stuck on it ..grayish in colour ..probaly acts
like Uv or IR filter... maybe some one can help me.. anyway it is this
bit that has gone browny almost burnt colour ..so when projector comes
on it looks yellowish..Does anyone know what this filter is exactly
?..where I can get it ..as I am sure it is not that expensive
...probably gray bit of tinted glass will do a similar job ..(like the
ones on the car ) except this is about 1" sqaure and only 2mm thick..

for pic see
http://www.ozads.net/mc/lcd.jpg

the front filter ... you can just see the brown on it ..

tNX ahead

mc wrote:
> Bought this one second hand ..not 100% ..
>
> has yellowish spot in middle of the screen or darkish grey on a blue
> screen .. I assume this is due to the lamp ..has done 1590hrs of the
> 2050 ..
> That one is not that noticable as the shadowing purple-red image of any
> black line or writing(text) on the screen..
>
> ie when the menu is up ..you can see all the proper image on there
> ..but any blakish type lines have like a shadow of that black line or
> writing to the left of it 3-4cm on a large screen... I've tried every
> adjustment but no luck ..it is as if the red side of projector is
> producing double images ..as all the white made images are ok ..so the
> colours are mixing properly
>
> has anyone stuck this on these projectors and how hard or easy is it to
> fix..
>
> I did open the unit ..but nothing that I can see that has any
> adjustments etc that can be made.
>
> the yellowing I suppose in the centre of the screen could be a dying
> lamp? I've never seen that before ..or is it from something else ..
>
> If some one is interested to purchase it like that I will consider it
> ..But I'd rather get it going as it is good watching movies with it ..as
> it can do 1200x1000 mode using a pc..
>
> TNX ahead
>

[Wdino]

That grey part is very likely the polarising filter - an essential part that
works with the LCD screen to provide the gradations in light output.
Usually these parts are only available to dealer repair stations. If you can
obtain one you will have to adjust the rotation of it for best black level
with a grey input signal. This ensures that the polarisation matches that of
the LCD screen.

The fault that occurs most often with LCD projectors that fits your symptoms
is that the transparent coating on one of the LCD screens becomes faulty.
The LCD material then does not get the right amount of electric field to
vary the LCD polarisation enough. Two solutions to that problem are, renew
the coating (if you have a vacuum chamber etc), replace that colour LCD
screen (if you can obtain the part). Then you will need a microscope, light
and patience to re-align the lcd screen.

Note that all lcd and dad projectors accumulate dust inside. Some people try
to clean them when the dust becomes apparent. DO NOT TOUCH THE SURFACES OF
THE LCD SCREENS. To remove dust the best answer is to use compressed air in
conjunction with a vacuum cleaner. Even then you will not be able to remove
all of the dust as some will stick due to humidity etc.

Best of luck.

[mc]

i sort of agree and disagree ..the "filter" maybe polarizing..but then
why is it just held in place with two aluminium lugs and hence ease of
possibility to rotate and move ..and hence if it is that critical then
certanly there is no mechanism to do that ie to be adjusted etc

to me these filters are probably Ir or UV type filters to stop radiation
getting to the LCD screens (and damaging them) ..and also out of the
projector ..I reckon in this case a lighly tinted bit grey glass like on
cars will do the job .. if I get a chance I will try it out .. just need
to get bit of tinted glass.. have grey perspex ..but it will probably
melt ..like the one they have in there already..

as far as LCD's YES the 3 are fixed in place (GLUED in some sort of
epoxy) and yes I can see how the 3 are critical in alignment and
projection through the prisms to the lenses .. to all align properly

Upon futher investigation ..the double image (red-purple) comes in play
when I connect the center one(LCD) to the pcb driver board.. there is a
possability that the driver is supplying the double image .. but no easy
way of me testing ..unless I have another board.. it could be the center
LCD ..I could try to disassemble it again and connect one of the other
LCDs to the center driver on the board .. or the center lcd to one of
the other drivers..the small ribbon type connector is not long enough to
test it out as it is..

I must add .. when I disconnect the centre LCD's there is no double
image (and no red colour) hence the problem is from the red channel
only .. yellow is from the burnt filter on the blue side..

tnx for the comments so far ..some have been helpfull



Wdino wrote:

> That grey part is very likely the polarising filter - an essential part that
> works with the LCD screen to provide the gradations in light output.
> Usually these parts are only available to dealer repair stations. If you can
> obtain one you will have to adjust the rotation of it for best black level
> with a grey input signal. This ensures that the polarisation matches that of
> the LCD screen.
>
> The fault that occurs most often with LCD projectors that fits your symptoms
> is that the transparent coating on one of the LCD screens becomes faulty.
> The LCD material then does not get the right amount of electric field to
> vary the LCD polarisation enough. Two solutions to that problem are, renew
> the coating (if you have a vacuum chamber etc), replace that colour LCD
> screen (if you can obtain the part). Then you will need a microscope, light
> and patience to re-align the lcd screen.
>
> Note that all lcd and dad projectors accumulate dust inside. Some people try
> to clean them when the dust becomes apparent. DO NOT TOUCH THE SURFACES OF
> THE LCD SCREENS. To remove dust the best answer is to use compressed air in
> conjunction with a vacuum cleaner. Even then you will not be able to remove
> all of the dust as some will stick due to humidity etc.
>
> Best of luck.
>
>

[Wdino]

The metal halide and similar arc lamps produce heaps of UV. They have a
quartz envelope which is transparent to UV. SO there is a glass UV filter
right at the interface with the lamp. There should not be any need for a UV
filter at the LCD screens.

[amstereo]

the blue displays have a UV filter to stop the lamp from whitning the blue
colour filter. UV and blue are so close to each other that the lamp leaches
the colour out of the filter, causeing permanent damage to the colour filter
on the lcd panel.

the uv filter is necessery for proper operation.

Obtain a uv filter if possible

[jward]

I am having the same problem with a Sony VPL-X1000. I bought a new
lamp and I have a yellow spot!


"amstereo" <amstereo@optushomeDOTcompanyDOTaustralia> wrote in message news:<40617633$0$31903$afc38c87@news.optusnet.com.au>...
> the blue displays have a UV filter to stop the lamp from whitning the blue
> colour filter. UV and blue are so close to each other that the lamp leaches
> the colour out of the filter, causeing permanent damage to the colour filter
> on the lcd panel.
>
> the uv filter is necessery for proper operation.
>
> Obtain a uv filter if possible