Optoma DLP Projector: Is this a color wheel issue?

Marcus96

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I have an Optoma HD131X (not to be confused with the name "HD131Xe", it is just "HD131X") which has always impressed me when it comes to image quality, especially regarding colour accuracy and vibrancy.

I have previously calibrated the projector, with amazing results (average Delta-E of <1 across the board), so I know colour performance is normally good. However recently I've noticed the image it projects starting to look a bit dull. I at first put this down to lamp hours (as it is nearly at 4000 out of it's estimated 6000 and putting into the BRIGHT setting does bring back some of that vibrancy, as I normally use Eco), however I then noticed some other strange things regarding colour.

I brought up a 16-235 grayscale test pattern and noticed that value "232" has a blue tinge to it. Lowering the contrast setting by 1 alleviates it. I then brought up some color test patterns on my AVS 709 disc and took some measurements with my colorimeter. On the 100% Color patterns, I noticed red and yellow were slightly undersatured (moslty by red going towards magenta and yellow towards green). Something I know a degrading lamp wouldn't cause. Then I brought up 75% brightness ones and these saturation issues sorted themselves out. For saturation measurements, 25%, 50% and 75% look to be all over the place (so re-calibration cannot solve it). So it's the brighter colours (in luminance, not saturation, that have the issue).

Playing with the settings a bit, I noticed if I drop the contrast to -11 from it's correct -3 value to display all video levels, this issue with the colours goes away on 100% patterns (literally, it suddenly pops from being off to accurate going from -10 to -11). However, at that contrast level, the image would be way too flat looking and dim, plus besides, it was perfectly fine until recently.

I also want to point out this issue significantly worsens with 24Hz and 50Hz signals (also with those refresh rates, the colour wheel emits a buzzing sound, but it's always done that). For 60Hz, it isn't all too bad.

I did some digging around on Google and it seems to point towards a colour wheel issue? Is there anyone here with any knowledge on DLP projectors if you can confirm if it's the colour wheel that is on it's way out? I have attatched two pictures to show the difference before and after lowering the contrast or gain on red. Help would be much appreciated, thanks in advance.

100% Red pattern with the projector at it's correct calibrated values
20220919_134711.jpg


100% Red pattern after lowering contrast/red gain (as it should be, or has been until recently)
20220919_134638.jpg
 
I've not seen this, but perhaps segments of the colour wheel are dirty, after all, it's the only source of colour (as long as the bulb's still outputting white). Here's a pic of a 131x colour wheel:
NEW-Original-Projector-Color-Wheel-for-Optoma-HD131X-HD141X-wheel-color.jpg_Q90.jpg_.jpg
Optoma used to give a 10 year colour guarantee, you could email their service centre describing the issue and they should be able diagnose it and see if you're covered.
Get technical support or make an enquiry - Optoma UK
If the worst comes to the worst colour wheels are fortunately fairly cheap.

(I recently got back a fair bit of brightness for a different Optoma by cleaning the bulb reflector using a soft camera brush, requires taking the bulb out of the housing, pretty easy. Cleaning the dust out of the light tunnel using a fluffy pipe cleaner also recovered some brightness, but that requires a lot of disassembly.)
 

Attachments

  • Optoma 10 Year Colour Guarantee.pdf
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Thank you for your suggestion! I believe it wouldn't hurt to send Optoma UK a message and see what they say, mentioning this 10 Year Colour Guarantee.

The color wheel is indeed the only source of colour, great point. Also the bulb still seems to be outputting more or less the same white as it did from my last calibration (grayscale DeltaE has barely shifted). If this fails, I am kinda tempted to find an Optoma specialist to give it a service (I don't trust myself to tear it down and fix/clean it without breaking anything 😂) as given this projector is now 9 years old, it could do with it. And maybe give it a complimentary new lamp as well?

I believe the one I have has an RGBRGB colour wheel, given mine is not the newer (and inferior) "e" model, but I could be wrong?

Another thing I meant to mention was, a few months ago, it's started making a strange noise when you first turn it on. Like a croak/screech sound (sometimes like a cricket, other times like a frog) which lasts about a second. This happens roughly 90% of the time I turn the projector on. It makes the sound as the lamp strikes up, and you can actually see a little flicker inside the lens in sync with the noise. It doesn't seem to affect the workings of the projector though?
 
I wonder if that is the colour wheel starting up? The fans start as normal a few seconds after this. This is the noise I am referring to:
 
ANOTHER UPDATE! I just displayed and RGB Ramps test pattern (built into the projector) which shows Red, Green, Blue and White greyscale ramps. As you may be able to see in this picture, the red has some weird banding going off, but the other colours are perfectly fine.

When I previously mentioned it's just the reds and yellows in brighter scenes affected by this, it would make perfect sense that it is something wrong with the red part of the colour wheel (and the red part is obviously used to make up yellow)? Is that part of the wheel perhaps dirty? Any ideas for a cause?
20220922_221441.jpg
 
That does sound like the colour wheel starting up. They spin and then light the bulb so it doesn't expose just one part of the glass colour wheel to the heat from the bulb and distort it. Mine just makes a faint squeak/whirring on startup. The rotation is then monitored by a light sensor and the projector should display a warning if there are any speed irregularities and shut down.

I'm not sure how a dirty red segment could produce banding since the segments flash across the entire image. If the banding looks pixelized maybe reduce the brilliant colour setting to zero (if it isn't), that can sometimes produce posterization/artifacting. The only time I've seen dark bands with my projector was due to some ripples in my screen (many years ago) that I eventually managed to flatten. Try the 100% red image with brilliant colour at zero (if it wasn't at 0).

When I contacted Optoma a couple of years ago they quoted me the below. I eventually cleaned it myself.
Before the Unit is Assessed:
Assessment Fee - £55.00 + VAT
Collection Freight - £12.50 + VAT
Once the Unit has been Assessed:
Labour - £25.00 + VAT
Parts needed for repair + VAT / no parts would be required if your unit just needs cleaning.
Return Freight - £12.50 + VAT
 
BrillaintColor has always been set to 1 (the lowest setting from 1-10, as that is equivalent to off on this projector). I have this projector had been calibrated to Rec.709/sRGB D65 standard, when I tried enabling it in the past, it just increased white brightness but not the colours (leaving an undersaturated looking image), and of course caused banding/posterization. I always keep that off.

I would clean it myself but knowing my recent luck with repairs not going to plan, I'd probably mess up the whole projector and with this one, the throw ratio/offset is perfect for how I have it mounted and no other projector can match it. Otherwise I would of probably upgraded to a 4K one long ago 😂
 
UPDATE: Just opened it up and thoroughly cleaned the colour wheel and the area around it inside. Unfortunately no improvement (maybe a bit more image brightness though)? Still some banding on the RGB ramps pattern and slightly skewed colours in the brightest of scenes! 😪

I have now contacted Optoma and mentioned the 10 Year Colour Guarantee thing and will see what they have to say.
 
Months later but thought I'd do a further update on this!

Optoma sadly said they couldn't service or repair it as it is an "end of life" product. However I did not give up. My first call was to try swapping out and replacing the colour wheel. I ordered the correct one for my projector, but when I installed it, it appeared to have cause terrible banding in another colour (blue ramp had a noisy and pale square in the middle of it) with red still unfixed. 😞 My assumption is I got gave the wrong colour wheel, even though they both look identical?

That failed, I gave the whole thing another deep clean. I even took out the lamp assembly and gave that a thorough clean too. Everything inside (the fan and lamp housing especially) were absolutely caked in dust. I cleaned all that out anyway. I kept the original colour wheel (as that is all I had to work with) and not only gave that another clean but the photosensor too. That appeared to have a tonne of dust on it. So I cleaned that off. As well as inside the projector with some compressed air (taking precautions to try not to get dust inside the optics, of course).

Upon reassembly and testing, I did notice some extra brightness once again (probably previously lost due to that dirty lamp housing). But the same weird colour issue affecting brighter red and yellow... 🤔 I then made tried making a slight adjustment to the color wheel index (from 135 to 139 on the 2X, and 130 to 137 on the 3X) and now the issue is much improved! As you can see in the image I attached (which I altered to look indicative of what I see in person), the end of the red spectrum is now nice and vibrant! 😁👍 Oh... and also the weird screeching sound on startup no longer happens either anymore, so BONUS!

RGB Ramp Pattern looking much better towards the end. Not perfect, but better.
20221111_114043.jpg


The image produced by the projector now looking much more vibrant again! 😍
20221220_172509.jpg


On a final note: It is not 100% perfect, but 99% there unlike about 80% before I would say. I'd say there is a slight pinkish tinted line about 3/4 of the way over about 1cm across on and red ramp going from 0 to 255 in a test pattern which is odd. But all the yellow issues appear to have been eradicated completely though! It's the best I could do anyway. I noticed everything looks to be nice and vibrant again, unlike previously! And any oddities I cannot really distinguish in real world content and very rarely in graphics content and UI menus. I don't exactly know if it is the colour wheel itself or the photosensor is at fault here (if anyone knows, hit me up with an assumption), but it'll do just nice! Giving my thanks to those who tried to help me previously! 🙂
 
Hello, could you please help me and tell me if this is a wheel issue? It is a new projector 0 lamp hours but out off 2 years warrenty.Thank you. Regards
IMG_20230704_084331.jpg
 

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