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Dim Mitsubishi WD-73738 DLP Telivision

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    #21
    Re: Dim Mitsubishi WD-73738 DLP Telivision

    Oh, for the brightness time. So I put the optical engine back in, put the TV together. Plugged a video source in, powered it up. Looked at it, it was dim. Went right to the back, pushed up on the HDMI cable, asked my wife it went brighter, she said it changed and flashed! I went up front, appears normal brightness now. I know HDMI 1 and 3 seem to have issues, I'd imagine HDMI 2 does as well.

    I've tried a different HDMI cable, the one we normally use for our TV, just in the rare case maybe my test HDMI cable has gone bad, but it didn't make a difference.
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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      #22
      Re: Dim Mitsubishi WD-73738 DLP Telivision

      Originally posted by Spork Schivago View Post
      Fans aren't sticky. I checked them. Was kinda surprised, because of how dirty they where. I don't see how I could possibly tear the optical engine apart anymore to clean it. I've taken it all apart, minus removing the heatsink on the DLP chip. I don't think there's anything I missed. I got some pics if you guys wanna see the engine I got in this.
      I provided a picture of a light engine that is in some of these mits, If you have a picture of yours, post it.
      After the light passes through the color wheel, it goes through a light tunnel, then through a few more lenses befoe it gets to the dmd chip. There should be a black plastic cover over the rest of the light engine optics
      Last edited by R_J; 04-01-2019, 07:45 PM.

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        #23
        Re: Dim Mitsubishi WD-73738 DLP Telivision

        Originally posted by Spork Schivago View Post
        Setting the setting to normal definitely makes it dimmer. The Bright setting or whatever it is, is currently the brightest for all of them.

        Thanks for that info! Definitely don't want to get hurt. I believe my best probes for my meter are rated for 600V. CAT 3 (I think it's 3). I remember seeing the 600V when I purchased them. For the meter, max is 700VAC, 1000DC.
        I am not sure I follow "Bright setting or whatever it is, is currently the brightest for all of them".... there is only two, normal and bright.... what's "all of them".

        anyway, you might try and measure the voltage when the bulb is "dull" and when you are able to cause the "brightness" to show up. I would expect the voltage to be manageable at 12v-50v or so.

        further, it would appear that you are "blaming" the hdmi... but I think the "hdmi" should be blaming the system.... my guess is you have a ground issue such that your "poor" hdmi cable is providing the ground needed by the system... just a guess.

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          #24
          Re: Dim Mitsubishi WD-73738 DLP Telivision

          Originally posted by R_J View Post
          I provided a picture of a light engine that is in some of these mits, If you have a picture of yours, post it.
          After the light passes through the color wheel, it goes through a light tunnel, then through a few more lenses befoe it gets to the dmd chip. There should be a black plastic cover over the rest of the light engine optics
          I apologize for not doing this sooner. I've been having some issues with my memory and how I feel. Feels like I've been hit by a locamotive, all the time now. Seen the neurologist the other day and she thinks it's from my white matter. Says the MRIs show it's going away. She's got another MRI scheduled and now an EEG. For the EEG, they want me to go 24 hours or so without sleep. I think they're looking for seizures with the EEG.

          It just makes it hard to work on this for some reason. I turn the TV on today, I hit the menu button but on the remote, same thing, goes in a loop, like the menu button is stuck. But this was with the remote. And the video source would just cut out, cut in. Every few seconds. As soon as the picture would come, it'd cut out, sound would cut out as well, and come right back, like it's stuck in some sort of loop.

          I tried pushing on the HDMI input, I removed it, reinserted it, couldn't get it to stop. Power cycled the TV, etc.
          Attached Files
          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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            #25
            Re: Dim Mitsubishi WD-73738 DLP Telivision

            Originally posted by budwich View Post
            I am not sure I follow "Bright setting or whatever it is, is currently the brightest for all of them".... there is only two, normal and bright.... what's "all of them".

            anyway, you might try and measure the voltage when the bulb is "dull" and when you are able to cause the "brightness" to show up. I would expect the voltage to be manageable at 12v-50v or so.

            further, it would appear that you are "blaming" the hdmi... but I think the "hdmi" should be blaming the system.... my guess is you have a ground issue such that your "poor" hdmi cable is providing the ground needed by the system... just a guess.
            There's more then two settings. There's Standard, there's Dynamic or something like that. I cannot get into the menu to check currently because of the "looping" I described in the post before this.

            When I grabbed the HDMI cable today, there was a static shock...maybe that provides a clue?
            -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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              #26
              Re: Dim Mitsubishi WD-73738 DLP Telivision

              .
              Last edited by R_J; 04-02-2019, 10:44 AM.

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                #27
                Re: Dim Mitsubishi WD-73738 DLP Telivision

                That UV filter, that was before I cleaned it. Now, it looks real clean. So does the colour wheel. I think I know that access panel you're talking about now. Are you thinking dirt would cause this TV's video source to cycle like it's cycling? I would think if it was dirt, the TV wouldn't get bright. It'd always be dark...
                -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                  #28
                  Re: Dim Mitsubishi WD-73738 DLP Telivision

                  Originally posted by Spork Schivago View Post
                  There's more then two settings. There's Standard, there's Dynamic or something like that. I cannot get into the menu to check currently because of the "looping" I described in the post before this.

                  When I grabbed the HDMI cable today, there was a static shock...maybe that provides a clue?
                  I wonder if we are talking about the same thing. I find it hard to believe that they would "dynamize" a lamp level setting... not sure how you could cause this to happen fast enough with a bulb and video. Anyways, if you get a chance, measure the bulb voltage at standard and again at bright to see if there is any difference. "shocking" may be a problem but it depends on what kind of surface you were moving across and other things (dryness, etc).

                  Take care of your health as I suspect they get much TV up in the "promise land"... :-)

                  Further: you are likely looking at the WRONG setting for the "lamp energy"..... you appear to be looking at "picture mode" which has a number of different settings... This parameter does not really have anything to do with "lamp energy" which has only two choices - standard and bright.
                  Last edited by budwich; 04-02-2019, 01:11 PM.

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                    #29
                    Re: Dim Mitsubishi WD-73738 DLP Telivision

                    If the video becomes good at some point, then It's not a dust issue in the light engine, likely something in the video circuit, try using another input, something other than hdmi.
                    It could be bad smd elctrolytics on the video board.
                    When the picture is bright or when it is darker, how does the menu look, is it also brighter/darker.

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                      #30
                      Re: Dim Mitsubishi WD-73738 DLP Telivision

                      I believe most DLP TVs start slightly dimmer and get gradually brighter. The process is only a few minutes. This may be a mechanism to prolong lamp life, which makes a lot of sense.

                      Similar to a soft-start motor so you don't ramp up the speed and hence the electrical current in the motor which causes it to get hot or risk burn out.

                      In a DLP lamp, you may soft-start the lamp to get it lit, then gradually increase the current to achieve required brightness but you don't ramp up the current immediately or you risk burning out the lamp prematurely.

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                        #31
                        Re: Dim Mitsubishi WD-73738 DLP Telivision

                        Originally posted by budwich View Post
                        I wonder if we are talking about the same thing. I find it hard to believe that they would "dynamize" a lamp level setting... not sure how you could cause this to happen fast enough with a bulb and video. Anyways, if you get a chance, measure the bulb voltage at standard and again at bright to see if there is any difference. "shocking" may be a problem but it depends on what kind of surface you were moving across and other things (dryness, etc).

                        Take care of your health as I suspect they get much TV up in the "promise land"... :-)

                        Further: you are likely looking at the WRONG setting for the "lamp energy"..... you appear to be looking at "picture mode" which has a number of different settings... This parameter does not really have anything to do with "lamp energy" which has only two choices - standard and bright.
                        Okay, then I am in the wrong setting. I must have been in picture mode. I am thinking there are two problems here and they are probably very much related. I am thinking of holding off on trying to figure out the dimness, until the other problem is fixed.

                        The other problem is the video keeps resetting. The backlight stays on, that is, the lamp does not turn off, and this problem might occur only when the TV is dim, or it might occur when it's bright or dim. The video source, including the sound, cuts off and then comes back on, it takes about 2 seconds, and just repeats non-stop. A power cycle temporarily fixed it in the past, but this time around, it has not. What would cause that? I thought loose HDMI cables, but I do not think that is the case...
                        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                          #32
                          Re: Dim Mitsubishi WD-73738 DLP Telivision

                          Originally posted by R_J View Post
                          If the video becomes good at some point, then It's not a dust issue in the light engine, likely something in the video circuit, try using another input, something other than hdmi.
                          It could be bad smd elctrolytics on the video board.
                          When the picture is bright or when it is darker, how does the menu look, is it also brighter/darker.
                          I believe the menu is also darker, but I will have to verify. Right now, I couldn't get the video to stop cycling, regardless of what HDMI input I had it on, however, I wasn't able to test the other input types, such as RCA. However, I believe the HDMI ports weren't causing this problem, because the OSD (menu) would cycle with it. I hit the menu button on the remote control, not the physical TV. I think once this problem is fixed, perhaps the brightness will be fixed. But where to start with this problem? I don't know enough about DLPs.
                          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                            #33
                            Re: Dim Mitsubishi WD-73738 DLP Telivision

                            Originally posted by Unspun01 View Post
                            I believe most DLP TVs start slightly dimmer and get gradually brighter. The process is only a few minutes. This may be a mechanism to prolong lamp life, which makes a lot of sense.

                            Similar to a soft-start motor so you don't ramp up the speed and hence the electrical current in the motor which causes it to get hot or risk burn out.

                            In a DLP lamp, you may soft-start the lamp to get it lit, then gradually increase the current to achieve required brightness but you don't ramp up the current immediately or you risk burning out the lamp prematurely.
                            That makes sense. A warm-up period.
                            -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                              #34
                              Re: Dim Mitsubishi WD-73738 DLP Telivision

                              Holy cow! I think I _FINALLY_!!!!! figured out the problem! I was looking at colour wheels on eBay for this TV, trying to find a part, because internet says for Mitsubishi 2011 model DLPs, 0061 is Lamp Enable Not Issued and the reason is Possible bad Colour Wheel.

                              I seen on ebay they got this tape or glue or something on the middle metal spinning disc (that the colours attach to). I thought maybe that had come off. Some wheels on eBay said if the black tape wasn't at the right colour as the original wheel, to move it to the proper colour. I thought maybe this "marker" came off so I removed the colour wheel again to check. It was still in place.

                              So, I removed the sensor board, and low and behold, the wires are burnt, one missing it's insulation all together for like half an inch. Board itself looks bad and I will post pics after dinner.
                              -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                                #35
                                Re: Dim Mitsubishi WD-73738 DLP Telivision

                                What do you guys think? Having hard time finding a replacement PCB. Was thinking the photointerrupter is probably good, because we get a picture sometimes. Figured maybe those two wires, Y and R, being shorted out is causing the issue, and if I could not find a replacement board, perhaps I could somehow replace the wires. The connector that plugs into the DMD board (the one that comes off this photo sensor PCB) isn't really a common one. I have a bunch of different connectors that I save, just in case I need to replace one, but this has a little lock you gotta push down on to remove it. I don't have any like that.

                                What do you guys think? Try to replace the entire board or attempt a repair?
                                Attached Files
                                -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                                  #36
                                  Re: Dim Mitsubishi WD-73738 DLP Telivision

                                  there is nothing special about the wires other than perhaps they need to have some thermal value to prevent the insulation from melting. You can likely just splice / replace the run of wire or provide some insulation to ensure no shorts. Get your meter and check end to end continuity of each wire... that may tell you if the existing wire has an issue or not.

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                                    #37
                                    Re: Dim Mitsubishi WD-73738 DLP Telivision

                                    In almost all dlp sets, if the color wheel has an issue, the lamp will not light at all, this to prevent the lamp from burning the color wheel disc. The lamp does not have a soft start, it is just the way these (UHP) type of lamps operate, they get slightly brighter after a few minutes of operation. It is a mercury discharge lamp, and it acts like a mercury vapor street lamp.
                                    If there was a problem with the color wheel indexing, the color would be way off, If the colors are correct the indexing is correct.
                                    I have seen some intermitint solder connections on the plugs on the dmd board in the past.
                                    Last edited by R_J; 04-04-2019, 10:17 PM.

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                                      #38
                                      Re: Dim Mitsubishi WD-73738 DLP Telivision

                                      As indicated above... if the color wheel causes an issue (ie. such as the system is unable to detect proper spin speed), then in most cases, this type of error "usually" occurs at startup, and the lamp would normally not be "striken" (started). However, if the error occurs during "normal run" then its possible that the unit would then shut down the lamp to prevent damage to a slow wheel or otherwise. You can check this with a "viewing" test" such that when the image disappears, look "carefully" at the light engine to see if the lamp is still lit. Of course, if you can eventually get a display again, you could also check the "counters / errors" to see if there was a "0061" happening again.

                                      Further, in DLP land, brightness of an image is usually achieved in two ways: one from the actual bulb rating and two from the color wheel itself. On some designs, a "blank" / white segment is used for both sync AND improved brightness levels. I am not sure about the Mits design but other projector manufacturers (eg. optoma) use this mode. On your wheel, what is the colors segments specifically going around the wheel?

                                      Further: Looking at a bit of stuff around this, it would appear that perhaps, then sensor is able to determine intensity of light in terms of range such that the main control can decide on how long to "turn on" the dlp chip segments to brighten or reduce intensity. It maybe possible that the sensor is coated with gunk such that this "work" is wrong... or there is a wiring issue. There might be some checks for this or perhaps some cleaning (carefully) of the sensor. What maybe happening is that the sensor is not detecting sufficient brightness as "requested" by the controller, so the controller is upping the "dlp activity" level to get more brightness. However, the system feedback via the sensor still does not show the expected "improvement" (or runs out of "on off" cycles for the dlp) and thus eventually the system "errors" and shuts down.
                                      Last edited by budwich; 04-05-2019, 07:54 AM.

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                                        #39
                                        Re: Dim Mitsubishi WD-73738 DLP Telivision

                                        Originally posted by budwich View Post
                                        there is nothing special about the wires other than perhaps they need to have some thermal value to prevent the insulation from melting. You can likely just splice / replace the run of wire or provide some insulation to ensure no shorts. Get your meter and check end to end continuity of each wire... that may tell you if the existing wire has an issue or not.
                                        I'm going to do that. I'd love to replace the wires, rather than splicing into them, but I cannot identify the connector on the end, nor can I find my caliper, which would greatly help.

                                        Unfortunetly, I think cutting out the bad, putting new wire in is the way I gotta go with this. I've been reading, and some people with similar DLPs (not the exact same model, but close) say there's a heating issue where the colour wheel is, and it damages the wires and the photointerrupter. They replace the photointerrupter and try various things, like adding a fan to try and cool the area. I'd rather not do that, but I'm trying to think what could have caused this damage. If it's getting so hot, it's actually melting the insulation off the wires in there, then perhaps external cooling is the way to go.
                                        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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                                          #40
                                          Re: Dim Mitsubishi WD-73738 DLP Telivision

                                          Originally posted by R_J View Post
                                          In almost all dlp sets, if the color wheel has an issue, the lamp will not light at all, this to prevent the lamp from burning the color wheel disc. The lamp does not have a soft start, it is just the way these (UHP) type of lamps operate, they get slightly brighter after a few minutes of operation. It is a mercury discharge lamp, and it acts like a mercury vapor street lamp.
                                          If there was a problem with the color wheel indexing, the color would be way off, If the colors are correct the indexing is correct.
                                          I have seen some intermitint solder connections on the plugs on the dmd board in the past.
                                          Yeah, I don't understand how the colours could possible have looked right. That's why I was ruling out the colour wheel, because I did various tests, such as looking at the TV from an angle, and it was fine. Two of these wires, the Y and R ones, are shorting out. I can't see how the picture could have displayed properly at all. I understand why this would have caused the input source to cycle, but I cannot for the life of me understand how the picture was being displayed properly with the short....
                                          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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