Sony Data Projector vplfh31 3LCD Blue missing

[budwich]

Got this projector which has a problem with a lack of blue. Menu text is very yellow... expecting white. If I input a signal from a test disc via hdmi, a red screen image shows a uniform red as expect. Green similar while the blue does show but with non-uniformity. Looked at the in-polarizers. They are all good and clean. Running the projector to expose the light area in the prism block, shows each color well represented, all looking about the same intensity from the naked eye. Looking at the prism block itself and sending a light source back into the "out port", the individual panels of each color seem to look fine, IF I understand what my eyes are seeing and comparing each. I don't readily see much difference between any of them and certainly don't appear to have any "burnt" aspect.

I have read a bit about the care needed to do anything with the block in terms of panel changes and hence most replacements are sold as a "very expensive" block assembly.
As part of the troubleshooting, I was thinking that I could swap one of the panel around. Let's say the red for the blue and then see if the problem moves. That would then indicate that the "panel sandwich" (made up of lcd panel and out-polarizers, etc) has an issue as opposed to the driving electronics. Not sure what the resulting colors would look like with blue coming in and red going out. Is it safe to say that the ribbon cablings / pins out is the same for all the panel and that its only the optical components of the sandwich are changed... thus allowing for a temporary swap? At this point, I don't see how the "sandwich" is removed from the block but I have seen that "sandwiches" are sold as units. In this case the base code of the sandwich is lcx119 with different suffixes for the different colors, so I know that they can be removed / replaced in some form... but maybe with lots of "headaches" thereafter. :-(

Any hints or suggestion as to this approach would be welcomed before this ends up in the recycle bin. thanks

[Diah]

need first to prove if there are data go to blue section LCD.before replace . all three section RGB receive same data of B&W Data. but different control level of contrast & Brightness

[budwich]

OK. Thanks for this. My understanding of LCD projection is very limited as I have only used and worked with DLP ones and mostly therein with hdmi interface issues.
I disconnected the red and green panel cabling going to the block on then displayed a menu. Prior to that the menu lettering was very yellow with pale yellow cast over the reset of the screen which should have been black / grey. With those cables disconnected, the pale yellow cast over the rest of the screen was more dark grey and there was a very faint sign of blue lettering. From what you indicate, that would seem to mean the data is getting there but that the control levels might be having an issue maybe? Resetting color controls does not impact the results.
Are those levels "biased" with some form of DC input which is then changed by the data streams received by the panel?

Aside: I also tried a composite video input... the resulting picture was the same as the posted hdmi picture that I put in the first post.

[budwich]

Attached is a block diagram of the video processing section. Not sure I know what I am looking for. :-(

My guess would be all the inputs going in to the IC1801 panel driver??

[budwich]

Here is the blue panel driver.... lots of inputs :-)

[Diah]

i suspect blue LCD burn and the light filter which installed at front of it burn too or the film damaged.. i would suggest take out the glass filter and inspect it easy to find any discoloring or damage on it... same to the LCD self there are film glued at it

[Diah]

yes you have data .... as i said before all 3 share the same ...about the control level of brightness and contrast are digital at main processing same method used with LCD TV

replace one LCD are pain in ass... i am not sure if you can adjusted... i cant

[Diah]

but its not enough just unplug the R & G LCD.... you need to hide the light from both so you will have Blue picture to do adjustment or further test

[budwich]

i suspect blue LCD burn and the light filter which installed at front of it burn too or the film damaged.. i would suggest take out the glass filter and inspect it easy to find any discoloring or damage on it... same to the LCD self there are film glued at it

:-( not sure I follow things in terms of "burnt"... will there be discoloration or blocked image? When I send an led light into the out side port of assembly, I can look at each panel. They all looked the same with good color, no blotches and "fog". I can clearly see the light source led cob element of the flashlight that I am using thru each panel.

So my question then, can I move the blue panel "sandwich" over to the red position and similarly put the red in the vacant blue area. Will this damage the drivers? Is there any voltages associated with the panel driver IC that is used for setting the contrast and brightness reference?

[Diah]

first open the cover of assembly, unit there you will see the filters mounted before the LCDs.. its thin thin rectangular glass mounted on it color filter.. this could damage or burned

[Diah]

So my question then, can I move the blue panel "sandwich" over to the red position and similarly put the red in the vacant blue area. Will this damage the drivers? Is there any voltages associated with the panel driver IC that is used for setting the contrast and brightness reference?

i never tried or thought one day to open the lcd sandwich, because i think it need vacuum to assemble it again

but yours issue could be the green... not the blue... to my eyes it look yellow

[budwich]

You could be right about the green. I am "color deficient" with red / green plus... I can see colors but if one color is dominate, it "floods" any others in certain combinations. I have asked my "helper" who has good color vision what colors are showing at times to confirm things so some of those details that I have provided about colors are based on that confirmation.

Not sure that you understand what I have said. I have the prism block / assembly totally out of the machine. I can place a flashlight at the "out port" side of the block... that is where the final "picture output" is sent towards the lens system. I can then readily look at the "in side" of each "panel sandwich". I can clearly see thru each and the color are clearly red for the red one, green for the green one and blue for the blue one. By "clearly", I mean there is NO "fogging" or "burnt looking" areas. In fact, I can clearly see the details of the light source of the led flash light, the individual output leds are well defined... on this flashlight it has 5-6 leds in its array. This is why I don't understand how the blue panel could be "burnt" as I don't see any signs of "burntness". As mentioned ealier, I have taken each individual "in-polarizer" out to examine both sides... it is NOT part of the "sandwich"... they are seperate individual mounted plates. They are very clean and don't look burnt. They are not colored but just regular polarizers, light grey in color.

[Diah]

i do understand the problem you are in with this Sony... am talking on the reason why yellowish ( because of the one of Polarizers which installed before the LCD... you are now considering on the LCD self.. so i write take out the Polarizers and check them with light... to the eye they look clean.. but in fact they changed and danged because of the heat.

BTW they are same Polarize used by cheap Chinese LCD projector which installed between LED source and the LCD... sofar they are large size can be cut to replace many pieces for Sony or any other LCD Projector.

[budwich]

OK... I will see how this "surgery" can be done.

ADDED: attached is the out polarizers, Green and Blue paths. Blue one is definitely "burnt". Are these available anywhere at a reasonable cost?

[Diah]

OK... I will see how this "surgery" can be done.

ADDED: attached is the out polarizers, Green and Blue paths. Blue one is definitely "burnt". Are these available anywhere at a reasonable cost?

here we are.. take one from Chinese lcd one and cut it as glass.. just be careful the cut should be from the glass side not on the side of thin film surface

[Diah]

but hold on... why they are different color.... i am afraid u show the reflectors
can you show photo from the top to see the places of them

[budwich]

The picture is one from the green and one from the blue.... not the two from blue.

[budwich]

I haven't gotten much further on this in terms of success. I have question though about the LCD panels on an 3lcd projector. Are the panels all the same... meaning "monochrome" and that basically only filters / polarizers are the "color component" or is each panel a "normal" LCD and only the appropriate "sub pixel" is driven for a given color? Depending on that operation, maybe the blue lcd panel has an issue and not necessarily only the polarizer stages.

[budwich]

It appears that the 3 lcd panels are all the same (ie. monochrome). Replacing the prism assembly brought everything back to "normal".