Dim Mitsubishi WD-73738 DLP Telivision

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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...

[Unspun01]

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.

[R_J]

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.

[budwich]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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.

[Spork Schivago]

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...

[R_J]

Re: Dim Mitsubishi WD-73738 DLP Telivision

.

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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?

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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.

[budwich]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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.

[R_J]

Re: Dim Mitsubishi WD-73738 DLP Telivision

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

[Spork Schivago]

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.

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

Well, was wondering if a temp. sensor put it in limp mode. Also wondered if there was a sticky fan.

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.

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

It appears that you have the "bright" settings for "lamp energy" ... the manual appears to be severely lacking :-). Switch the setting to "standard" to see if you notice any difference.

As far as voltages, you might look around the boards for any labeling identifying any voltages. Of course, the first thing would be to watch the strike voltage (careful... these aren't going to be a few voltages... it will "bite" you if you don't take care. From there, monitor the voltage once lit, and for a while there after to see if any changes occur.


WARNING****** strike voltages maybe in the 5KV range so be very very careful!!!! not sure what your meter will take but certainly your body won't like it .... :-( you probably don't want to try top measure this voltage. Let the lamp start, once it starts, the circuit will switch out the strike voltage section and maintain its normal operating voltage which should be in some readable / safer range.

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.

[Spork Schivago]

Re: Dim Mitsubishi WD-73738 DLP Telivision

If the (spinning) color wheel is dirty, you can bet the other 4 or 5 lenses after the colorwheel are also dirty, that piece of glass between the lamp and the colorwheel is usually a UV filter, not just a piece of clear glass, so it can get discolored over time due to heat.

I cleaned the colour wheel and the UV filter. Is there more hidden lenses some where?

I cleaned the main mirror behind the screen. I cleaned the round glass ball looking thing.

Finally, we turn the TV back on, it's not bright. I go back, I push up on the HDMI cable, the video source flashes for a second, and the TV is bright. Could a bad HDMI port cause dimness or is the bad ports not related? I was thinking of trying to reflow those HDMI ports...

[RJARRRPCGP]

Re: Dim Mitsubishi WD-73738 DLP Telivision

It could have been a fan issue but if the 3rd party lamp does not have "exactly" the same "run current" draw, depending on what it was, it may have caused a run drive issue in the ballast. The meter check, along with the suggestion of changing the "lamp energy" option to see what happens, will start the investigation.

Well, was wondering if a temp. sensor put it in limp mode. Also wondered if there was a sticky fan.

[budwich]

Re: Dim Mitsubishi WD-73738 DLP Telivision

That may be because of the fan RPM being too low. A Mitsubishi DLP TV I saw 3 years ago, before it got condemned by 2016, I assume, uses a 12 V DC fan, just like a PC. I thought I saw a Delta in there, back in 2015, even when not a screamer, of course. That one was a socket 775 era DLP, IIRC. (said 2008 on the body, IIRC)

It could have been a fan issue but if the 3rd party lamp does not have "exactly" the same "run current" draw, depending on what it was, it may have caused a run drive issue in the ballast. The meter check, along with the suggestion of changing the "lamp energy" option to see what happens, will start the investigation.

[ajshoe]

Re: Dim Mitsubishi WD-73738 DLP Telivision

I'd bet your light engine is dirty. When you say it gets brighter over time - what time frame ?? you need to put a another tv next to it and compare. Its most likely not the ballast or bulb. another avenue would be to buy another bulb - they're fairly cheap now.

[RJARRRPCGP]

Re: Dim Mitsubishi WD-73738 DLP Telivision

How about this "story".... the first "replacement lamp" wasn't an OEM but a "third party" that may not have been the proper / "marginal" wattage for the system. It may have started OK... but during "lit operation" stressed the drive circuit of the ballast such that the circuit has a slightly higher "drive resistance" thus providing lower current.

That may be because of the fan RPM being too low. A Mitsubishi DLP TV I saw 3 years ago, before it got condemned by 2016, I assume, uses a 12 V DC fan, just like a PC. I thought I saw a Delta in there, back in 2015, even when not a screamer, of course. That one was a socket 775 era DLP, IIRC. (said 2008 on the body, IIRC)

[budwich]

Re: Dim Mitsubishi WD-73738 DLP Telivision

I ran across that article as well, and that's why I asked about the possibility of a dirty colour wheel. It was the only place in the optical engine I didn't get to clean. I was trying to think what else could have caused that guy's dimness in the optical engine.

How do I check the lamp energy setting? In the menu, it's currently set to Bright, which provides the brightest setting. It seems that the TV does reach a bright display, after it's been on for a bit.

The previous lamp, it was really bad after market. In this picture, you can see how the bulb is "hard-wired" to the housing. I cannot find any identifiable marks on the bulb either...

What voltages would I be looking for and where would I be looking for them at? I figure I could maybe watch the voltage going to the ballast, and maybe the voltage leaving the ballast, but what should they be?

It appears that you have the "bright" settings for "lamp energy" ... the manual appears to be severely lacking :-). Switch the setting to "standard" to see if you notice any difference.

As far as voltages, you might look around the boards for any labeling identifying any voltages. Of course, the first thing would be to watch the strike voltage (careful... these aren't going to be a few voltages... it will "bite" you if you don't take care. From there, monitor the voltage once lit, and for a while there after to see if any changes occur.


WARNING****** strike voltages maybe in the 5KV range so be very very careful!!!! not sure what your meter will take but certainly your body won't like it .... :-( you probably don't want to try top measure this voltage. Let the lamp start, once it starts, the circuit will switch out the strike voltage section and maintain its normal operating voltage which should be in some readable / safer range.

[R_J]

Re: Dim Mitsubishi WD-73738 DLP Telivision

If the (spinning) color wheel is dirty, you can bet the other 4 or 5 lenses after the colorwheel are also dirty, that piece of glass between the lamp and the colorwheel is usually a UV filter, not just a piece of clear glass, so it can get discolored over time due to heat.