Don't dump your CRT RPTV! - Page 355 - AVS Forum
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post #10621 of 12592 Old 04-18-2012, 09:00 AM
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I think that the last generations of Mitsubishi DLPs are very good, particularly if you're looking at models from 73 inches to 75 inches (the latter being Laservue).

Regarding the rainbow effect, these have pretty much been eliminated with the newer DLP's utilizing a color wheel that rotates much more rapidly than in earlier models. And of course the Laservue eliminates the rainbow effect altogether, as that it has three discrete color sources rather than a color wheel.

73-75 inches seems to be the sweet spot for DLPs given the power or intensity of the light sources used. Larger sets seem insufficiently bright with the image losing all punch to my eyes. With regard to the non-Laservue sets, Mitsubishi seems determined (possibly compelled) to use a lightbulb with a maximum of 180 W. The image on the larger sets seems "thin" and a bit insubstantial to me.

Regarding the colors blending together, this sounds like a defect to me, not an attribute of DLP at all.
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post #10622 of 12592 Old 04-18-2012, 09:04 AM
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Quote:
Originally Posted by taichi4 View Post

I think that the last generations of Mitsubishi DLPs are very good, particularly if you're looking at models from 73 inches to 75 inches (the latter being Laservue).

Regarding the rainbow effect, these have pretty much been eliminated with the newer DLP's utilizing a color wheel that rotates much more rapidly than in earlier models. And of course the Laservue eliminates the rainbow effect altogether, as that it has three discrete color sources rather than a color wheel.

73-75 inches seems to be the sweet spot for DLPs given the power or intensity of the light sources used. Larger sets seem insufficiently bright with the image losing all punch to my eyes. With regard to the non-Laservue sets, Mitsubishi seems determined (possibly compelled) to use a lightbulb with a maximum of 180 W. The image on the larger sets seems "thin" and a bit insubstantial to me.

Regarding the colors blending together, this sounds like a defect to me, not an attribute of DLP at all.

I wonder why they would not want to put larger bulbs as the screen gets larger. I really want an 80+ inch screen but it being "inferior" to the 73" due to the same bulb troubles me. Then again I don't like very bright images. On my Mits 55413 the "brightest" I'm willing to go is contrast at 27 and brightness around 30 I think.
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post #10623 of 12592 Old 04-18-2012, 09:37 AM
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Quote:
Originally Posted by Shady12 View Post

I wonder why they would not want to put larger bulbs as the screen gets larger. I really want an 80+ inch screen but it being "inferior" to the 73" due to the same bulb troubles me. Then again I don't like very bright images. On my Mits 55413 the "brightest" I'm willing to go is contrast at 27 and brightness around 30 I think.

I have to say that when I saw the new Mitsubishi 82 inch (82840?), it was not bad at all. In the current generation some of the models came with Clear Contrast screens, which absorb less of the light than the traditional screens, letting more of it through to the viewer. I didn't have a lot of time to play with the 82 inch, but the one with the Clear Contrast was pretty good, if you control the light in the room. However, the 73 inch models are affordable, large, and have very good PQ, occupying that sweet spot where 180 W is quite ample. Also, 3D is very good on the 73 inch models, dependent as it is on brightness.

I suspect that there are a couple of considerations factoring into why Mitsubishi appears stuck with the 150-180 W bulb. First, they want to be Energy Star compliant, so they want to use a bulb which draws less power. Secondly, heat is an issue, as it can affect the DLP optical block, and the materials used therein.

By the way, the DLP "engine" (the DMD chip) is not a perpetual motion machine, immune to degradation, as people think. The little semiconductor "mirrors" that drive the device can be biased with repeated electrical charging. Ideally, the semiconductors have to return to a neutral position, but there is a phenomenon wherein repeated stimulation biases the semiconductors in such a way that it takes a higher charge to drive them throughout their range of motion. I have a white paper somewhere on my computer on this subject.

This doesn't mean that the optical block doesn't have a long life span. In most circumstances, it does. But it makes me reflect on the robustness of the 75-year-old technology behind the CRT tubes. And they sure do pump out a lot of light.
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post #10624 of 12592 Old 04-18-2012, 02:56 PM
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I figured this would be a good place to ask a question about crt focus (if not feel free to direct me elsewhere
I got a 10 year old hitachi 51" uwx model and i'm wondering what the correct method to focus the lens on top of the crt's is? Do i adjust the wingnut slider or the regular bolt slider on the other side of the lens casing and is it safe to touch the lens casing and wingnut adjusments when the unit is turned on?
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post #10625 of 12592 Old 04-18-2012, 08:36 PM
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I had a 2000 72 inch Mitsubishi WS-73905 that I loved, but the picture was turning dim, purple and seemed to be on it's last legs. Luckily in searching the Internet for recommendations on a new TV I came across this forum and made contact with Mr. Bob. After talking it over with Bob and my supervisor (aka wife) and we decided to let Bob work his magic on what we thought was a burned out set. All I can say is wow. The reason I bought this set was the 9 inch CRT's and the picture quality. When new I had the set adjusted by an ISF calibrator, but it now looks better than it did new.

Bob takes his time, explains what he does, gives you accurate pricing and his work is amazing.

One other issue we had is the lack of an HDMI as my system is "quaint" or if for sale at Mercedes pre-owned. I have an Aerial Acoustic speaker set-up (10-T Fronts, sub, center and surrounds) with an older Bryston SP 1.7 and 9BSST 5 channel amp. Bob installed an Oppo 95, a HD Fury and I now have Blue Ray through the Oppo, Direct TV, and then SDDVD's/Netflix/web tv that runs thru the HD Fury. The picture is awesome. Most importantly my supervisor is pleased.

The blacks are incredible, the "red push" eradication tweak as Bob called it resulted in the most amazing colors the TV has ever had.

I cannot say enough about Bob or the magic he can work. He is also a gentleman and can be trusted to give you sage advice about what may be possible. We saved thousands with this and have a TV that will last for years.

Thanks Mr. Bob!
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post #10626 of 12592 Old 04-18-2012, 09:24 PM
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Fantastic! Can you post a few photos?

Kudos to you, Bob.
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post #10627 of 12592 Old 04-19-2012, 08:51 AM
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I had some time last night to take the screen off my set and give it a "good cleaning". It has been a good 8 months since the last optical cleaning and it needed it. Clean the the mirror and lenses, and touched up the electro focus. If time permits, I'll touch up covergnece, touch up the grayscale, re-align the colors and touch up mechanical focus.

Mr. Bob has also been involved on getting my tv to look superb, he is a Master on CRT tech. and I would also recommend Mr Bob to anyone.

I'll dust off the camera and take some shots. LONG LIVE CRT!!!

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post #10628 of 12592 Old 04-19-2012, 11:55 AM
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Where do I go to find out if adjusting the mechanical/lens focus is going to cause any sort of high voltage shock?
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post #10629 of 12592 Old 04-19-2012, 12:28 PM
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Quote:
Originally Posted by Mik James View Post

Where do I go to find out if adjusting the mechanical/lens focus is going to cause any sort of high voltage shock?

If it did, we'd all be dead.

But if you're truly concerned, just snap on a pair of disposable rubber gloves.
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post #10630 of 12592 Old 04-19-2012, 12:34 PM
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Awesome a reply thanks so I shouldn't have any issue adjusting the wingnuts on the lens casings in my 51uwx20b when it's turned on right?
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post #10631 of 12592 Old 04-19-2012, 12:35 PM
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What about if I accidentally touch the casings as Ill be adjusting from the port in the back. I probably sound like a noob but better safe than 50000 volts of sorry
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post #10632 of 12592 Old 04-19-2012, 05:13 PM
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I am new here and joined because of the helpfulness of Mr. Bob's youtube videos. I have a 46 Inch RCA P46733AT which I got for free from a friend. It still works nice for being made in 1996 but I'm a noob at anything projection based. At this point, I'm learning about the service mode and codes but have not been able to come across the service/repair manual for it so I keep doing online research to learn what I can.

Thanks Mr. Bob, for your great videos and sharing your expertise with us less technically savvy folks.

Cheers
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post #10633 of 12592 Old 04-20-2012, 11:57 AM - Thread Starter
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Quote:
Originally Posted by Boss Rhinos View Post

I had a 2000 72 inch Mitsubishi WS-73905 that I loved, but the picture was turning dim, purple and seemed to be on it's last legs. Luckily in searching the Internet for recommendations on a new TV I came across this forum and made contact with Mr. Bob. After talking it over with Bob and my supervisor (aka wife) and we decided to let Bob work his magic on what we thought was a burned out set. All I can say is wow. The reason I bought this set was the 9 inch CRT's and the picture quality. When new I had the set adjusted by an ISF calibrator, but it now looks better than it did new.

Bob takes his time, explains what he does, gives you accurate pricing and his work is amazing.

One other issue we had is the lack of an HDMI as my system is "quaint" or if for sale at Mercedes pre-owned. I have an Aerial Acoustic speaker set-up (10-T Fronts, sub, center and surrounds) with an older Bryston SP 1.7 and 9BSST 5 channel amp. Bob installed an Oppo 95, a HD Fury and I now have Blue Ray through the Oppo, Direct TV, and then SDDVD's/Netflix/web tv that runs thru the HD Fury. The picture is awesome. Most importantly my supervisor is pleased.

The blacks are incredible, the "red push" eradication tweak as Bob called it resulted in the most amazing colors the TV has ever had.

I cannot say enough about Bob or the magic he can work. He is also a gentleman and can be trusted to give you sage advice about what may be possible. We saved thousands with this and have a TV that will last for years.

Thanks Mr. Bob!

This was quite a fun calibration. Larry has a Mit 73", from the early days of HD in this country, which still had those delicious color isolation and decoder registers in them, the ones that disappeared permanently from the service menu in the next year's model, the WS 73907. As such it was very straightforward to realign the color decoding to truly linear performance, allowing the brilliant blues and greens to stay center stage and vivid while fleshtones stay perfect as well - impossible to do with factory issue red push, inherent by design in all Mitsubishi CRT RPTVs. The combination of having all colors dynamic and present, with none hotter at the expense of the others (the definition of red push which is another word for blue/green diminish), is truly hypnotic.

He had me replace the mylar mirror with my own glass front surface mirror, which had been sitting in my garage for a couple of years, and this alone increased his light output measurably. Along with the optics cleaning and tilting his set down to allow the sweet spot to hit him right between the eyes while sitting and watching video rather than sailing over his head as it always had been before, the net effect was to make his picture tangibly stronger and palpably more effortless than it was before.

He also had me do the shimming op for the overscan reduction, resulting in tighter resolution and of course revealing the outer parts of the picture that he had always been missing.

And it was fun! His son helped me on some of the more strenuous activities, like installing the mirror and constantly lifting off that big 73" viewscreen and putting it on again later, and his wife was the consummate hostess during all 3 visits. On the last visit he had me reprogram his Home Theater Master remote for macros, having changed out substantial parts of his system, including taking his now malfunctioning old and unnecessary Lumagen outa there. As it turned out, the original tech never needed to install it in the first place, because it was only being used to transcode to component inputting. With a few strokes in his user menu I did the same thing without it, which was one of the first things I did when I arrived the first time.


I need more 10 year old CRT sets to revive and make look better than new! Bring them on, I'm ready for ya -

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post #10634 of 12592 Old 04-20-2012, 12:37 PM - Thread Starter
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Quote:
Originally Posted by Mik James View Post

What about if I accidentally touch the casings as Ill be adjusting from the port in the back. I probably sound like a noob but better safe than 50000 volts of sorry

Focusing should be done from the front, preferably with my proprietary Cantilever Technique, which you can find described on one of my youtube videos.

If you stay out of the back of the set, you won't be anywhere near high voltage. The optical cavity where the lenses and their wingnuts has none at all, so no worries.

If you choose to remove the back, which is completely unnecessary for focusing either optically or electronically, you're on your own! Wear the rubber gloves!

I am always ready to do a phone consult on all of these facets of the calibration process, including the Cantilever Technique. Not all of the ops needed to truly correct a big screen to its full potential are self-explanatory!



b

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post #10635 of 12592 Old 04-20-2012, 12:39 PM - Thread Starter
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Quote:
Originally Posted by Jetrell69 View Post

I am new here and joined because of the helpfulness of Mr. Bob's youtube videos. I have a 46 Inch RCA P46733AT which I got for free from a friend. It still works nice for being made in 1996 but I'm a noob at anything projection based. At this point, I'm learning about the service mode and codes but have not been able to come across the service/repair manual for it so I keep doing online research to learn what I can.

Thanks Mr. Bob, for your great videos and sharing your expertise with us less technically savvy folks.

Cheers

You got it!

b

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post #10636 of 12592 Old 04-20-2012, 12:45 PM - Thread Starter
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Quote:
Originally Posted by taichi4 View Post

I have to say that when I saw the new Mitsubishi 82 inch (82840?), it was not bad at all. In the current generation some of the models came with Clear Contrast screens, which absorb less of the light than the traditional screens, letting more of it through to the viewer. I didn't have a lot of time to play with the 82 inch, but the one with the Clear Contrast was pretty good, if you control the light in the room. However, the 73 inch models are affordable, large, and have very good PQ, occupying that sweet spot where 180 W is quite ample. Also, 3D is very good on the 73 inch models, dependent as it is on brightness.

I suspect that there are a couple of considerations factoring into why Mitsubishi appears stuck with the 150-180 W bulb. First, they want to be Energy Star compliant, so they want to use a bulb which draws less power. Secondly, heat is an issue, as it can affect the DLP optical block, and the materials used therein.

By the way, the DLP "engine" (the DMD chip) is not a perpetual motion machine, immune to degradation, as people think. The little semiconductor "mirrors" that drive the device can be biased with repeated electrical charging. Ideally, the semiconductors have to return to a neutral position, but there is a phenomenon wherein repeated stimulation biases the semiconductors in such a way that it takes a higher charge to drive them throughout their range of motion. I have a white paper somewhere on my computer on this subject.

This doesn't mean that the optical block doesn't have a long life span. In most circumstances, it does. But it makes me reflect on the robustness of the 75-year-old technology behind the CRT tubes. And they sure do pump out a lot of light.

I have seen the little mirrors start to get "stuck" on or off one by one, creating "speckles" of white and black all across the screen. In such cases the DMD chip needs to be replaced. It's not hard to do and saves your set, esp. since everything else about the set is still just fine. It just takes a very careful treatment of the situation, as everything in there has to go back in just the way it came out, without disturbance, and without screwing up anything in the process. This DMD replacement op has become a growing part of my business.

Don't forget that all projection tech requires that the optics be cleaned eventually. On CRT that means every year, but on a DLP that can mean that at the 5 year mark your picture has become just as bleary as those of CRT tech with dirty optics. No dynamic punch anymore, looks like your set is worn out (retailers love that!)

Having that optics cleaning done revives your set like you would not believe. It's like getting a new set, with just an afternoon's worth of work!


b

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post #10637 of 12592 Old 04-20-2012, 03:09 PM
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Thanks for the reply bob . I'm not actually going into the lower back of the set where the electronics are though. I took the brown wood cover that covers both the electronics area on the bottom and the access to the area behind the screen where the mirror and top of the guns/lens casings are (there's is a 1/2 inch thick board seperating the two compartments) and sawed it in half so I can get into the top compartment with the wingnut adjustments without having all the electronics exposed underneath where i'm working. That way i could adjust the focus with a good quality still image while looking at the back of the screen.
I'm a little confused though because as we'll as a wingnut adjustment there is also a similar bolt adjustment on the other side of each lens casing (not sure what the other bolt does) and i wasn't sure if the mechanical focus should be adjusted when the set is turned on or painstakingly incrementally adjusted turning the set on and off (Theres also a chance that i'd accidentally brush again'st the lens casings on my way to the wingnut adjustment if i go through the back.. I've heard of the cantilever technique but i don't see any way to seperate the top and bottom of my hitachi 51uwx20b (is that how it's done?) If that would work better i'd give it a shot. Do you have an idea what page it's on or should i just start from the top
Thanks for your help.
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post #10638 of 12592 Old 04-20-2012, 03:35 PM - Thread Starter
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That second nut is just a guide, it follows the first one at the wingnut automatically. You remove the viewscreen, forget about sawing anything at all, that's completely unnecessary, any more than separating the top from the bottom is. And viewing from the back during focusing is not as good as viewing from the front, I've tried.

Here's the video -

http://www.youtube.com/watch?v=8yTrU6Mb1tg

The advantage to using the CT over all other methods is that you can check and double check your focusing without ever altering the focusing that's on there now. You don't loosen the wingnut or change the setting of the lens as held in place by tightening the wingnut.

Therefore if your focusing is already at its absolute tightest, you don't change anything. You do the CT, check your results, and if it's the best it can be on all 3 images already, you back off and leave it completely alone without having altered anything.

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post #10639 of 12592 Old 04-20-2012, 05:06 PM
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Alright i'm kinda getting it, but what is being cantilevered? the screen?
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post #10640 of 12592 Old 04-20-2012, 05:25 PM
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You got it!

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If you lived near me and I could afford your services I'd have you give my projection TV the works....especially with all the compliments you and your work have received.

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post #10641 of 12592 Old 04-20-2012, 06:36 PM
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Quote:
Originally Posted by Mik James View Post

Alright i'm kinda getting it, but what is being cantilevered? the screen?

Mik, I don't know your particular TV model, but it sounds like you are doing everything wrong. RPTVs are designed to be focused without difficulty. You are creating your own difficulty by going in the wrong way.

Go in from the front. Move the screen to the side. Focus. Move the screen to the other side. Focus. Cantilever is complication. Focus is easy.
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post #10642 of 12592 Old 04-20-2012, 07:15 PM
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Yeah that kind of makes sense except you can never get the screen perfectly flat on when you move it to each side, unless i have a different model than you. I'll give that a shot, thanks.
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post #10643 of 12592 Old 04-21-2012, 03:31 PM - Thread Starter
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Quote:
Originally Posted by Mik James View Post

Alright i'm kinda getting it, but what is being cantilevered? the screen?

Usually the viewscreen is hinging/cantilevering at the top, sometimes at the bottom depending on design. For a Hitachi I believe it's the top.

I don't displace the mirror to the side and focus just so you can get your hands in there, because you're not getting a completely front-on reading of your focusing that way. And as has been said, you can't be sure your screen is dead center at its at-rest point when there is no support on it because it's hanging out with one of its sides waving in the air in the center, because you've moved the entire screen to the side.

I use 480 rather than 1080 so I can actually readily see the scanlines themselves, which is what I recommend be focused upon.

If you've looked at the video I recommended, you see that you bring the center of the viewscreen out and then in, over and over while changing that color's position held by the wingnut, till going forward and back gives you a completely balanced result. When your image starts to go out of focus exactly as much when pulling your screen out and away from the mirror as when you're pushing it in towards the mirror, you're done. If that happens before changing anything, you're done without changing anything. This is the only mechanical focusing method that delivers that. Yours may already be perfect. With the CT, it can stay that way without the actual focusing ever being disturbed.

Some have trouble getting what I am trying to say here and on the video, and for those who do, please set up a coaching call with me and I'll guide you thru it every step of the way on the phone.

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post #10644 of 12592 Old 04-21-2012, 03:39 PM - Thread Starter
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Quote:
Originally Posted by Jetrell69 View Post

If you lived near me and I could afford your services I'd have you give my projection TV the works....especially with all the compliments you and your work have received.


Thank you.

And once you have all that established, send me a plane ticket and I'll deliver for you right there in your viewing room. If you can't afford a plane ticket and/or a full on calibration, get together with me on the phone and let's get started. There are many ways to save money here. No reason for you to not have the finest picture your set is capable of - or at least the best you can afford to have at present, till you can have more. It doesn't need to be all or nothing, here.

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post #10645 of 12592 Old 04-22-2012, 02:43 PM
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Thanks for trying but i'm still not getting it.
The only question i had that hasn' been directly answered is whether or not it is safe to be messing around with the the optical focus when the crt's are in operation. Is there any part of the top compartment of the television where the mirror and lens casings are that electricity is flowing when the tv is turned on??
Before i try any method i need that question answered directly.
Also what are your rates for consult calls bob?
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post #10646 of 12592 Old 04-22-2012, 04:03 PM
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Hello, its been awhile since i posted in here. I have a quick question. I have a chance to pick up a Mitsubishi WS-73909 the only problem is that there is no picture. The owner says it turns on then turns right back off. This sounds loke it may be a convergance chip or the caps? Im just wondering if this would be worth snagging if i can get it below $100 ?

Thank you
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post #10647 of 12592 Old 04-22-2012, 04:22 PM - Thread Starter
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Quote:
Originally Posted by Mik James View Post

Thanks for trying but i'm still not getting it.
The only question i had that hasn' been directly answered is whether or not it is safe to be messing around with the the optical focus when the crt's are in operation. Is there any part of the top compartment of the television where the mirror and lens casings are that electricity is flowing when the tv is turned on??
Before i try any method i need that question answered directly.
Also what are your rates for consult calls bob?

No HV is present anywhere close to the optical cavity. Nothing but ultra low voltage that cannot hurt you.

$ is best not discussed on these boards. Feel free to contact me directly.

b

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post #10648 of 12592 Old 04-22-2012, 04:57 PM
 
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Quote:
Originally Posted by Mr Bob View Post

Focusing should be done from the front, preferably with my proprietary Cantilever Technique, which you can find described on one of my youtube videos.

If you stay out of the back of the set, you won't be anywhere near high voltage. The optical cavity where the lenses and their wingnuts has none at all, so no worries.

If you choose to remove the back, which is completely unnecessary for focusing either optically or electronically, you're on your own! Wear the rubber gloves!

I am always ready to do a phone consult on all of these facets of the calibration process, including the Cantilever Technique. Not all of the ops needed to truly correct a big screen to its full potential are self-explanatory!



b

Now could this be also done relatively easily with a team of two people as well? One person with a keen eye watching the screen, another person slowly adjusting the focus from the back. That would be almost as good as the typical techniqe we'd use for a dense/sharp (usually 1920 by 1080 digital) front projector, right?

- 2 Bunny
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post #10649 of 12592 Old 04-22-2012, 05:05 PM - Thread Starter
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Yes if you want to have 2 people on it. But still the tiny increments possible with moving the screen instead of the lens because of the CT, have the advantage over turning a lens barrel itself while you watch. There can be tinier increments by moving the screen rather than the lens itself.

b

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post #10650 of 12592 Old 04-23-2012, 06:29 PM
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Could you wear sunglasses and try to focus on the phosphor grain while staring at the mirror?
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