Thanks
The TFT I used was a NEC Multisync 400V. The difference to the NEC Multisync 400 being a narrower viewing angle. While the viewing angle of my display really sucked as a monintor when I tested it prior to disassembling it, this really does not matter in a projector. BTW I did state that in my first post but I know about that searching issue... Since the display had to be mounted in a tilted position I had to mod the OHP housing. Although I did not plan on doing that in the beginning, I am now glad I had to, since I think it looks better than a cubic housing. At least a littlebit. Repeating earlier posts:
I first wanted to elongate both the 10-pin and the 45-pin ribbon cable. The ribbon cables are both 0.5mm pitch. I tried soldering on that and failed, it was just too close together. Thus the tilted design wich allows for the 45-pin cable to go without elongation. Luckily on the 10-pin cable there where spots on the PCB for everyone of the 10 connections. These spots, little (maybe .5*.5mm) are used for testing the unit after manufacturing I think. These spots are present on the Display-side PCB and the main PCB so I could connect those using a 80-pin UDMA 100 Harddisc cable. (Only 10 pins of that of course). The pitch on these cables still is slightly larger than .5mm so connecting the 45 pins of the other flexcable would have been really difficult even with soldering points...
If your display has these points, too, consider going this route (I don't know your soldering skills, of course...)
Use a soldering needle (those 12 volts 5$ ones) to apply little "balls" of soldering "tin?" to the points, which you apply soldering "honey" to before you start. (The honey being an ACID FREE) product. Then use an average soldering iron (very fine tip, I ground mine to be needle-sharp) to just liquify the "balls" one by one and push the "silvered" cables into it. I really don't know if it is nonsense voodoo or not, but I heard people say when soldering on sensitive electronics you should heat up the soldering iron and unplug it before touching the PCB with it. I did not do this on the display side, but did it on the PCB side and my unit works, what can I say.
I did take pictures of the display-side soldering, but with a normal camera and presumably it will take years for them to be developes. It is not that interesting anyway. I did take digital photos just now of the PCB-side connection. Hope they help.
Lokost: Seems like a good explanation, thanks.
Myren: I'm afraid tilting the display or fresnel is less than an optimal solution for keystone correction, since by doing so you get different distances from the display to the projection lens and hence an image that is focused in the middle but off focus at top and bottom. Or is that compensated by the different distances of the projection lens to the bottom and top of the projection surface? I tried it and it did not work well, but maybe I am missing something. I use digital keystone correction. Using the projector for watching TV with descaler (<-- rocks) I use a linear correction filter. That is a feature built into descaler. It allows you to strech the image into a trapezoid opposite to the diplayed trapezoid, so u get an even picture in the end.
I guess there really is a lot left to say.
Frank Batzen
The TFT I used was a NEC Multisync 400V. The difference to the NEC Multisync 400 being a narrower viewing angle. While the viewing angle of my display really sucked as a monintor when I tested it prior to disassembling it, this really does not matter in a projector. BTW I did state that in my first post but I know about that searching issue... Since the display had to be mounted in a tilted position I had to mod the OHP housing. Although I did not plan on doing that in the beginning, I am now glad I had to, since I think it looks better than a cubic housing. At least a littlebit. Repeating earlier posts:
I first wanted to elongate both the 10-pin and the 45-pin ribbon cable. The ribbon cables are both 0.5mm pitch. I tried soldering on that and failed, it was just too close together. Thus the tilted design wich allows for the 45-pin cable to go without elongation. Luckily on the 10-pin cable there where spots on the PCB for everyone of the 10 connections. These spots, little (maybe .5*.5mm) are used for testing the unit after manufacturing I think. These spots are present on the Display-side PCB and the main PCB so I could connect those using a 80-pin UDMA 100 Harddisc cable. (Only 10 pins of that of course). The pitch on these cables still is slightly larger than .5mm so connecting the 45 pins of the other flexcable would have been really difficult even with soldering points...
If your display has these points, too, consider going this route (I don't know your soldering skills, of course...)
Use a soldering needle (those 12 volts 5$ ones) to apply little "balls" of soldering "tin?" to the points, which you apply soldering "honey" to before you start. (The honey being an ACID FREE) product. Then use an average soldering iron (very fine tip, I ground mine to be needle-sharp) to just liquify the "balls" one by one and push the "silvered" cables into it. I really don't know if it is nonsense voodoo or not, but I heard people say when soldering on sensitive electronics you should heat up the soldering iron and unplug it before touching the PCB with it. I did not do this on the display side, but did it on the PCB side and my unit works, what can I say.
I did take pictures of the display-side soldering, but with a normal camera and presumably it will take years for them to be developes. It is not that interesting anyway. I did take digital photos just now of the PCB-side connection. Hope they help.
Lokost: Seems like a good explanation, thanks.
Myren: I'm afraid tilting the display or fresnel is less than an optimal solution for keystone correction, since by doing so you get different distances from the display to the projection lens and hence an image that is focused in the middle but off focus at top and bottom. Or is that compensated by the different distances of the projection lens to the bottom and top of the projection surface? I tried it and it did not work well, but maybe I am missing something. I use digital keystone correction. Using the projector for watching TV with descaler (<-- rocks) I use a linear correction filter. That is a feature built into descaler. It allows you to strech the image into a trapezoid opposite to the diplayed trapezoid, so u get an even picture in the end.
I guess there really is a lot left to say.
Frank Batzen
Attachments
Tim:
Didn't see you where asking me!
The picture I get is very bright. Too bright for some scenes. Especially since the image is a little blurry at the outside, scenes with men in white shirts really lead to a lot of "ghosting" around these shirts. I think 400W might be overkill. Not meaning to be an ***, but I think Europeans are a lot more conscious about power consumption than most Americans and watching movies would feel much better only consuming 250W. Can movies be watched in a light room? NO. Blacks on the screen are, as you know, created by not shining light on them (by the projector). A wall that is not black can therefore not display black scenes. It just isn't possible. In a lit room I can see the picture, maybe I could even tell wich movie it is, but it is not watchable. You really want a room with absolutely no light in it. I even taped all cracks of the OHP housing shut, since even one little crack that light shines throug, degrades the image quality considerably.
Frank Batzen.
Frankbatzen has not attached an image.😀
Didn't see you where asking me!
The picture I get is very bright. Too bright for some scenes. Especially since the image is a little blurry at the outside, scenes with men in white shirts really lead to a lot of "ghosting" around these shirts. I think 400W might be overkill. Not meaning to be an ***, but I think Europeans are a lot more conscious about power consumption than most Americans and watching movies would feel much better only consuming 250W. Can movies be watched in a light room? NO. Blacks on the screen are, as you know, created by not shining light on them (by the projector). A wall that is not black can therefore not display black scenes. It just isn't possible. In a lit room I can see the picture, maybe I could even tell wich movie it is, but it is not watchable. You really want a room with absolutely no light in it. I even taped all cracks of the OHP housing shut, since even one little crack that light shines throug, degrades the image quality considerably.
Frank Batzen.
Frankbatzen has not attached an image.😀
Cool Pix
Hey frankbatzen, cool pix. Your advice/pix on the LCD panel preparation will help once I get a my LCD panel.
But one big question, when you say that the outside of the picture is blurry, what do you mean? Does it seem like the a failure of the optics? The lens can't resolve sharply for the entire picture range? Or is the picture more washed out like, leading one to belive its a shortcoming of the lcd panel??
By the way, not sure if its news to frankbatzen, but a review of the NEC 400V by Zdnet says...
".... But achieving true black and uniform colors on our test proved nearly impossible. Hues were washed out in some parts of the screen while saturated in others, depending on both the angle of viewing and position of natural or artificial lighting. Tilting and swiveling the monitor toward or away from the light source helped somewhat, but often we were left dodging and weaving in our seat to get the truest color... "
Link
I think some of frankbatzen's image "problems" (I don't know if there really that bothersome or not) could be due the the lcd panal which looks to be 1999 era, with 150:1 contrast ratio.
An important point to frankbatzen's choice of a LCD panel is that its 14.1", which is important to fit on OHP displays. BUT (and this is a big but). 14.1" are not really part of the current LCD market, and always have been for more budget minded consumers ie. there response time may be large or unlisted, there contrast ratios will be < 250:1.
This is the only reason that I haven't sprung on a LCD myself yet (my OHP and cheapy VGA lcd panel come on friday). I really want a 14.1" LCD panel, but I also want modern 15" specs (>350:1 contrast, <35ms total response time.
Ha ha, whats the joke about men willing to pay anything for an extra inch??? Well here we're trying to loss an inch 🙂
BTW that article I was referring to a few posts back was from Residential Systems magazine, feb '02, a home theater installation trade magazine that you can get for free by somehow getting on the mailing list (I'm guessing?) or if you attend a conference like I did. VERY intersting statistic is the fact that DLP's now control 55% of the current front projection market place (up from 40% last year) DESPITE costing more $2500 than the average LCD style projector. The big new develpment for DLP's the new 16:9 native aspect ratio chips. Someones gotta figure out how to get a hold of those DLP chips
🙂
Hey frankbatzen, cool pix. Your advice/pix on the LCD panel preparation will help once I get a my LCD panel.
But one big question, when you say that the outside of the picture is blurry, what do you mean? Does it seem like the a failure of the optics? The lens can't resolve sharply for the entire picture range? Or is the picture more washed out like, leading one to belive its a shortcoming of the lcd panel??
By the way, not sure if its news to frankbatzen, but a review of the NEC 400V by Zdnet says...
".... But achieving true black and uniform colors on our test proved nearly impossible. Hues were washed out in some parts of the screen while saturated in others, depending on both the angle of viewing and position of natural or artificial lighting. Tilting and swiveling the monitor toward or away from the light source helped somewhat, but often we were left dodging and weaving in our seat to get the truest color... "
Link
I think some of frankbatzen's image "problems" (I don't know if there really that bothersome or not) could be due the the lcd panal which looks to be 1999 era, with 150:1 contrast ratio.
An important point to frankbatzen's choice of a LCD panel is that its 14.1", which is important to fit on OHP displays. BUT (and this is a big but). 14.1" are not really part of the current LCD market, and always have been for more budget minded consumers ie. there response time may be large or unlisted, there contrast ratios will be < 250:1.
This is the only reason that I haven't sprung on a LCD myself yet (my OHP and cheapy VGA lcd panel come on friday). I really want a 14.1" LCD panel, but I also want modern 15" specs (>350:1 contrast, <35ms total response time.
Ha ha, whats the joke about men willing to pay anything for an extra inch??? Well here we're trying to loss an inch 🙂
BTW that article I was referring to a few posts back was from Residential Systems magazine, feb '02, a home theater installation trade magazine that you can get for free by somehow getting on the mailing list (I'm guessing?) or if you attend a conference like I did. VERY intersting statistic is the fact that DLP's now control 55% of the current front projection market place (up from 40% last year) DESPITE costing more $2500 than the average LCD style projector. The big new develpment for DLP's the new 16:9 native aspect ratio chips. Someones gotta figure out how to get a hold of those DLP chips
🙂
Great setup, frankbatzen! Could you post some screenshots? I know that doesn't always give a fair representation of the image, but it's something. I agree with you on the wattage issue...that's why I liked the Fluorex 65watt bulb (over 8000 lumens!), but it would hardly qualify as a point source light. And there is definitely a trade-off between lumens and contrast with those high power bulbs.
While we're on the topic, here is some additional info on cheap Metal Halide lighting systems:
Cheap MH
Sorry if it has been posted before. It is some discussion on the "Metal Halide Lighting For $100" link I posted earlier (also on my website).
I should receive my 800x600 OHP panel by the end of the week. Hopefully. Keep up the good work, everyone.
-f4
While we're on the topic, here is some additional info on cheap Metal Halide lighting systems:
Cheap MH
Sorry if it has been posted before. It is some discussion on the "Metal Halide Lighting For $100" link I posted earlier (also on my website).
I should receive my 800x600 OHP panel by the end of the week. Hopefully. Keep up the good work, everyone.
-f4
VP140 specs
The Viewsonic VP140 is supposed to have 250:1 contrast ratio. Response time is unlisted...
It's a gamble; That the VP140 sucks, vs the difficulty of retrofitting the OHP with a bigger fresnel (>12" width, to accomodate a 15") and getting the light evenly spread. That certainly can be done...
I spose if some 15" panel had BOTH width and height controls, you could just crunch the display down to fit. You'd be wasting some pixels, but so-what? You'd still have the response time and contrast ratio...
The VP140 has a width control (as does the Nview Z350) but not height. This may be common practice for some reason...
It would suck to have an egg-shaped planet earth when the "Universal Pictures" header comes on...That's what my S-video output of my Matrox G450 dual head does. Yeah, it shows up on the TV, but everyone's taller than they really are! I've tried every combination of controls to no avail...
The Viewsonic VP140 is supposed to have 250:1 contrast ratio. Response time is unlisted...
It's a gamble; That the VP140 sucks, vs the difficulty of retrofitting the OHP with a bigger fresnel (>12" width, to accomodate a 15") and getting the light evenly spread. That certainly can be done...
I spose if some 15" panel had BOTH width and height controls, you could just crunch the display down to fit. You'd be wasting some pixels, but so-what? You'd still have the response time and contrast ratio...
The VP140 has a width control (as does the Nview Z350) but not height. This may be common practice for some reason...
It would suck to have an egg-shaped planet earth when the "Universal Pictures" header comes on...That's what my S-video output of my Matrox G450 dual head does. Yeah, it shows up on the TV, but everyone's taller than they really are! I've tried every combination of controls to no avail...
Joe, i am sure you must have already tried this, but i have a Radeon VE (dual display, and TV out), and through the display settings in windows i can totally modify the width and height of an image displayed on the tv. The matrox should have this.
CRT Projection
Excellent work everyone.
As you've probably figured, I'm a newbie here. But unlike osme of the others, I've read every line of every post and actually made notes (I love notepad 🙂 )
Moving right along.....
After reading everything, I've become very interested in joing Scot_Lad on his CRT journey.
If you're reading this, I'd love to get some more info.
I basically have all the equipment that I need for this lens etc. What I need now, is a way to get the damn 14" monitor to shine brighter. or a way to add a light source to it.
From there, I should be sitting pretty (I think)
Thanks to everyone for a great discussion that has kept me up for 3 days trying to catch up.
Keep it all up.
MarcDM.
Excellent work everyone.
As you've probably figured, I'm a newbie here. But unlike osme of the others, I've read every line of every post and actually made notes (I love notepad 🙂 )
Moving right along.....
After reading everything, I've become very interested in joing Scot_Lad on his CRT journey.
If you're reading this, I'd love to get some more info.
I basically have all the equipment that I need for this lens etc. What I need now, is a way to get the damn 14" monitor to shine brighter. or a way to add a light source to it.
From there, I should be sitting pretty (I think)
Thanks to everyone for a great discussion that has kept me up for 3 days trying to catch up.
Keep it all up.
MarcDM.
CRT route
MarcDM
If You notised in one of my posts, I have kontakted a friend of mine, who is currently studying electronics and he is going to ask one of his teatchers how to "boost" the brightnes on a standard PC-monitor. I hope to post the reply in a few weeks.
My theory is that most monitors are built of standard parts and therefore have redundant capacity to fitt diffrent applications. My hope is that by replacing some of the electronics I can get more brightnes.
but as I wrote, this is theory.
I also hope to hear from Scot_lad and his results.
By for now
MarcDM
If You notised in one of my posts, I have kontakted a friend of mine, who is currently studying electronics and he is going to ask one of his teatchers how to "boost" the brightnes on a standard PC-monitor. I hope to post the reply in a few weeks.
My theory is that most monitors are built of standard parts and therefore have redundant capacity to fitt diffrent applications. My hope is that by replacing some of the electronics I can get more brightnes.
but as I wrote, this is theory.
I also hope to hear from Scot_lad and his results.
By for now
CRTs
Hello again,
Sorry I've been away for a while, not had a spare second to write my results on a post, and right now I'm still at work and can't write anything til tomorrow. Sorry!!
Basically, there are a couple of ways to boost the brightness of a CRT. I'm using a very simple 5" Black and white CRT based design, and it is very easy to figure out the workings of it.
Unfortunately, you can't just replace the brightness control to go higher, as it is usually a variable resistor which varies from 0 Ohms (brightest) to around 1 M-Ohm (dark). In a monitor, this would only be more complicated because it could have electronic control. Also, you can't use a light source, as the pixels themselves are the light source. Although if you have any ideas on this I'd be interested to hear them.
You want to get the contrast as high as possible, because when you start boosting the brightness, you don't want the image to get washed out. Also, increased brightness will wear the tube (CRT) out more quickly. This shouldn't be too much of a problem though.
If you figure out where the luminance signal goes before it gets into the tube as a stream of electrons (I'm assuming you know basic CRT theory - if not I'll explain), you could amplify this. Although you'll need to figure out where the signal goes, and at each stage, what the maximum voltage swing may be.
Once again, I'm really sorry I can't be more accurate at this time, all my notes and workings are at home, and I won't be back there til tomorrow night, late. So look for some posts in a couple days. Sorry.
Hello again,
Sorry I've been away for a while, not had a spare second to write my results on a post, and right now I'm still at work and can't write anything til tomorrow. Sorry!!
Basically, there are a couple of ways to boost the brightness of a CRT. I'm using a very simple 5" Black and white CRT based design, and it is very easy to figure out the workings of it.
Unfortunately, you can't just replace the brightness control to go higher, as it is usually a variable resistor which varies from 0 Ohms (brightest) to around 1 M-Ohm (dark). In a monitor, this would only be more complicated because it could have electronic control. Also, you can't use a light source, as the pixels themselves are the light source. Although if you have any ideas on this I'd be interested to hear them.
You want to get the contrast as high as possible, because when you start boosting the brightness, you don't want the image to get washed out. Also, increased brightness will wear the tube (CRT) out more quickly. This shouldn't be too much of a problem though.
If you figure out where the luminance signal goes before it gets into the tube as a stream of electrons (I'm assuming you know basic CRT theory - if not I'll explain), you could amplify this. Although you'll need to figure out where the signal goes, and at each stage, what the maximum voltage swing may be.
Once again, I'm really sorry I can't be more accurate at this time, all my notes and workings are at home, and I won't be back there til tomorrow night, late. So look for some posts in a couple days. Sorry.
jjasniew-
Have you seen a program called Powerstrip? It's available from www.entechtaiwan.com. A lot of people (including myself) on the HTPC board at www.avsforum.com use the program to set custom timings and resolutions, and to reduce overscan. Look on the above-mentioned forum for help with the programs' settings - especially a post by Mark Rejhon (Definitive Guide to Custom Resolutions, or something similar, from October 2000) and there's another particularly good post from one of the moderators, Xcel.
I hope that this is what you're after.
brad
Have you seen a program called Powerstrip? It's available from www.entechtaiwan.com. A lot of people (including myself) on the HTPC board at www.avsforum.com use the program to set custom timings and resolutions, and to reduce overscan. Look on the above-mentioned forum for help with the programs' settings - especially a post by Mark Rejhon (Definitive Guide to Custom Resolutions, or something similar, from October 2000) and there's another particularly good post from one of the moderators, Xcel.
I hope that this is what you're after.
brad
Thanks!
I downloaded power strip - will check it out - Thanks for the pointer!
Seeing as I did buy the Viewsonic "scaler" box and expect to run the display at time with it, I'd still be stuck with the stage aperature problem of my OHP using a 15" display.
I noticed all but one of the VP140s are sold off ebay - anyone from here get one?
On increasing the brightness of a CRT;
When I was in high school, (approaching 30 year ago) I disconnected the horizontal and verticle deflection coil from an old 27" B&W TV, hooked them together so that they would draw a circle with a sine wave input...
An artifact that I remember was that the beam became very bright. I assume that happened because the circuit no longer had to drive the horizontal deflection coil, all the extra energy going into the HV transformer. (The two are typically run from the same circuit)
So I assume one way to get increased brightness is to increase the HV to the tube, the so-called "anode" voltage. To do this, you
need to increase the drive voltage to the HV "flyback" transformer - which inadvertantly happened in my teenage experiment.
Unfortunately, this is going to take some real engineering and will probably not be presentable as a general case that will work for just any monitor. Also, you'd be working with the most dangerous voltage levels of all, far greater and more lethal than in any tube amplifier...You need special stuff just to measure it and be able to say how much it is. Otherwise, I guess you could just say that the picture got brighter...
I think any monitor meeting the "TCO 95" standard has been specifically engineered for reduced radiations (xray, etc). Guess what goes "up" with anode voltage? So perhaps on a modern monitor, you'd have to undo all the "stops" they engineered into it to keep the anode voltage from going too high, to meet this emissions standard.
I dont think you want to work with monitors >5yrs old, unless you happen upon a few "new old stock" ones. Most approaching this age are well-worn out.
I'm saying all this only to say it's going to be quite an engineering challenge, to make some new and fresh CRT monitor do what you want it to do. Just as it is to make a LCD monitor into a projection panel.
I gave up when I took a normal brightness monitor, held my lens in front of it and could not see anything projected, that wasnt washed out by the ambient light level just scattering off the tube face pointing straight up. I've repeated this experiment a few times in my life, ultimately convincing myself each time that it's more toward "fat chance" than I want to deal with.
IMHO, it would be easier to save your pennies and then bid aggressively on a Barco CRT projector off ebay or buy one from inventory solutions. The better ones are extremely sophisticated devices, using specially designed liquid cooled CRTs designed to run high anode voltages, for a very bright light emission. Just that its useful to note what it takes to make something with good enough performance to be an actual product.
I downloaded power strip - will check it out - Thanks for the pointer!
Seeing as I did buy the Viewsonic "scaler" box and expect to run the display at time with it, I'd still be stuck with the stage aperature problem of my OHP using a 15" display.
I noticed all but one of the VP140s are sold off ebay - anyone from here get one?
On increasing the brightness of a CRT;
When I was in high school, (approaching 30 year ago) I disconnected the horizontal and verticle deflection coil from an old 27" B&W TV, hooked them together so that they would draw a circle with a sine wave input...
An artifact that I remember was that the beam became very bright. I assume that happened because the circuit no longer had to drive the horizontal deflection coil, all the extra energy going into the HV transformer. (The two are typically run from the same circuit)
So I assume one way to get increased brightness is to increase the HV to the tube, the so-called "anode" voltage. To do this, you
need to increase the drive voltage to the HV "flyback" transformer - which inadvertantly happened in my teenage experiment.
Unfortunately, this is going to take some real engineering and will probably not be presentable as a general case that will work for just any monitor. Also, you'd be working with the most dangerous voltage levels of all, far greater and more lethal than in any tube amplifier...You need special stuff just to measure it and be able to say how much it is. Otherwise, I guess you could just say that the picture got brighter...
I think any monitor meeting the "TCO 95" standard has been specifically engineered for reduced radiations (xray, etc). Guess what goes "up" with anode voltage? So perhaps on a modern monitor, you'd have to undo all the "stops" they engineered into it to keep the anode voltage from going too high, to meet this emissions standard.
I dont think you want to work with monitors >5yrs old, unless you happen upon a few "new old stock" ones. Most approaching this age are well-worn out.
I'm saying all this only to say it's going to be quite an engineering challenge, to make some new and fresh CRT monitor do what you want it to do. Just as it is to make a LCD monitor into a projection panel.
I gave up when I took a normal brightness monitor, held my lens in front of it and could not see anything projected, that wasnt washed out by the ambient light level just scattering off the tube face pointing straight up. I've repeated this experiment a few times in my life, ultimately convincing myself each time that it's more toward "fat chance" than I want to deal with.
IMHO, it would be easier to save your pennies and then bid aggressively on a Barco CRT projector off ebay or buy one from inventory solutions. The better ones are extremely sophisticated devices, using specially designed liquid cooled CRTs designed to run high anode voltages, for a very bright light emission. Just that its useful to note what it takes to make something with good enough performance to be an actual product.
Hi Joe,
good point, what you said about CRTs. The guys who want to overdrive monitor brightness have to consider that all kind of monitor tubes must be driven within their specifications or things may happen which aren't good for health. Not only high voltage (up to 30 Kv !), also amperage for some electronic components would increase, so a lot of them would be damaged.
Along with electron beam amperage, the power of deflection circuit has to grow, the electron canon has to cope the power.
There's only a small range to modify "normal" CRT devices, which cannot produce the quantum leap, which would be required for projection.
xblocker
good point, what you said about CRTs. The guys who want to overdrive monitor brightness have to consider that all kind of monitor tubes must be driven within their specifications or things may happen which aren't good for health. Not only high voltage (up to 30 Kv !), also amperage for some electronic components would increase, so a lot of them would be damaged.
Along with electron beam amperage, the power of deflection circuit has to grow, the electron canon has to cope the power.
There's only a small range to modify "normal" CRT devices, which cannot produce the quantum leap, which would be required for projection.
xblocker
Amperage
OK first of all, I'm presuming by 'amperage' you mean 'current'.
jjasniew:
The reason your image was brigher when you only drew a circle or whatever, was nothing to do with the tube only driving the horizontal deflection coil. Basically, there is one gun, which outputs a set amount of electrons and hence a set brightness. The horizontal and vertical deflection coils simply spread the beam out (in an organised manner) all over the screen. Imagine a hose pipe spraying water over a garden. If it is pointed in one spot it will get very wet, but if you spray it all over the garden, the water will be spread evenly across the whole garden, see?
If you disconnect one set of coils, the picture is effectively squashed into either a horizontal or vertical line (the water is spread over a lower area, hence wetter grass), so the entire brightness of the picture is spread over a lower area, hence a brigher image.
You could always get a 14" CRT, and compress the image into a 5" square. This would give an incredibly bright image, but for the fact that the phosphors inside the CRT have a maximum output before they start to burn, so it wouldn't be feasible, but you get the idea.
As for messing about with high voltage anodes, there's more simple ways to it than that. Like I said earlier, I'l not be home til tomorrow so I can't tell you more details than that.
I'm glad to see some interest at last in the CRT approach, it's really increased my motivation to investigate further so watch this space for more info when I can post it. One reason I suppose I got interested is because OHPs are so big and completely unlike any kind of home cinema system, and more like a classroom (sorry, fresh out of uni, just glad to see the back of these things).
Will post later. Keep up the good work. Scot_lad loves all the CRT guys!!!
(and yes, all the LCD guys too)
OK first of all, I'm presuming by 'amperage' you mean 'current'.
jjasniew:
The reason your image was brigher when you only drew a circle or whatever, was nothing to do with the tube only driving the horizontal deflection coil. Basically, there is one gun, which outputs a set amount of electrons and hence a set brightness. The horizontal and vertical deflection coils simply spread the beam out (in an organised manner) all over the screen. Imagine a hose pipe spraying water over a garden. If it is pointed in one spot it will get very wet, but if you spray it all over the garden, the water will be spread evenly across the whole garden, see?
If you disconnect one set of coils, the picture is effectively squashed into either a horizontal or vertical line (the water is spread over a lower area, hence wetter grass), so the entire brightness of the picture is spread over a lower area, hence a brigher image.
You could always get a 14" CRT, and compress the image into a 5" square. This would give an incredibly bright image, but for the fact that the phosphors inside the CRT have a maximum output before they start to burn, so it wouldn't be feasible, but you get the idea.
As for messing about with high voltage anodes, there's more simple ways to it than that. Like I said earlier, I'l not be home til tomorrow so I can't tell you more details than that.
I'm glad to see some interest at last in the CRT approach, it's really increased my motivation to investigate further so watch this space for more info when I can post it. One reason I suppose I got interested is because OHPs are so big and completely unlike any kind of home cinema system, and more like a classroom (sorry, fresh out of uni, just glad to see the back of these things).
Will post later. Keep up the good work. Scot_lad loves all the CRT guys!!!
(and yes, all the LCD guys too)
Scot_lad, of course you can decrease horizontal and vertical deflection to concentrate image on a smaller spot. But the electron beam have the same power and will make the same 'pixel' size. That means, the resolution of this new image of 5" will be about 1/8 of normal resolution!
Just some thoughts from Frank Sinatra.
xblocker
Just some thoughts from Frank Sinatra.
xblocker
Electron Beam size
Damn, now there's something I hadn't thought of. Of course, it doesn't affect me because I'm already using a 5" TV. Incidentally, the reason I wrote it all was because I'd come home from the pub, where I'd been watching the football on a nice big CRT projection TV.
I am wavering between removing the 5" CRT (high-brightness) that I have from an old CRT projector, and building something new and reliable around that. But that sounds a bit complicated.
Damn, now there's something I hadn't thought of. Of course, it doesn't affect me because I'm already using a 5" TV. Incidentally, the reason I wrote it all was because I'd come home from the pub, where I'd been watching the football on a nice big CRT projection TV.
I am wavering between removing the 5" CRT (high-brightness) that I have from an old CRT projector, and building something new and reliable around that. But that sounds a bit complicated.
Back on planet earth...
Hey Scot_lad and Hellfire, I think you've sparked some interest in CRT tubes for me as well.
After spending quite some time trying figure out the costs and complexities of DLP projectors*, reading various white papers and devlopers documentation, I always ran into its comparisons with CRT tubes, which DLP is just now exceding to a degree ( DLP ALWAYS had a significant light output advantage however). And got very intrested in this (CRT) decidedly low tech approach.
I get my 7K lumen projector friday. cant wait to try it out, But will honestly most likely sell it and try to recoup at least some of my money on ebay ( after spending considerable effort on water cooling my PC to get rid of noise, the last thing I want is a screaming projector!) If I stay the LCD route, I will follow the steps in the $100 MH lamp guide and get bigger fensel(s) for a 15" screen.
The CRT thing I'm look forward spending a few hours tomorrow morning to catch with you guy's (I previously have always skipped the crt posts). BTW, I did a quick test on my trinitron 21" , diverging the rays down to its lowest size has a VERY noticable effect on its brightness, or at least is contrast, whites seem MUCH whiter, blues blue'er etc....UGGH its late, catch tomorrow!
Few quick facts on Ti's DLP
*$10k for a starter kit (but what a damn cool looking starter kit, complete with a GUI interface...), $5k for each controller and chip (DMD), a bit cheaper for over 100 quanties, everthing 1024 x 768, not their lastest 16X9 or HD-2 chip 🙁
Hey Scot_lad and Hellfire, I think you've sparked some interest in CRT tubes for me as well.
After spending quite some time trying figure out the costs and complexities of DLP projectors*, reading various white papers and devlopers documentation, I always ran into its comparisons with CRT tubes, which DLP is just now exceding to a degree ( DLP ALWAYS had a significant light output advantage however). And got very intrested in this (CRT) decidedly low tech approach.
I get my 7K lumen projector friday. cant wait to try it out, But will honestly most likely sell it and try to recoup at least some of my money on ebay ( after spending considerable effort on water cooling my PC to get rid of noise, the last thing I want is a screaming projector!) If I stay the LCD route, I will follow the steps in the $100 MH lamp guide and get bigger fensel(s) for a 15" screen.
The CRT thing I'm look forward spending a few hours tomorrow morning to catch with you guy's (I previously have always skipped the crt posts). BTW, I did a quick test on my trinitron 21" , diverging the rays down to its lowest size has a VERY noticable effect on its brightness, or at least is contrast, whites seem MUCH whiter, blues blue'er etc....UGGH its late, catch tomorrow!
Few quick facts on Ti's DLP
*$10k for a starter kit (but what a damn cool looking starter kit, complete with a GUI interface...), $5k for each controller and chip (DMD), a bit cheaper for over 100 quanties, everthing 1024 x 768, not their lastest 16X9 or HD-2 chip 🙁
Time to experiment
Well, I've done some research. Asked some questions and I'm about to do some tests. It's easter holidays here, so I might get some time to take that monitor apart and try a thing or two.
I have a friend who has quite a lot of experience repairing TVs so I'm gonna get his help maybe to try figure out a way to get more light out of this MarkVision monitor.
Wish me luck.
I'll let y'all know how it goes on Sunday.
Marc D.M.
Well, I've done some research. Asked some questions and I'm about to do some tests. It's easter holidays here, so I might get some time to take that monitor apart and try a thing or two.
I have a friend who has quite a lot of experience repairing TVs so I'm gonna get his help maybe to try figure out a way to get more light out of this MarkVision monitor.
Wish me luck.
I'll let y'all know how it goes on Sunday.
Marc D.M.
CRT route
Good luck MarcDM ! 🙂
I have not heard from my friend so I can not help You for the moment but I think Scot_lad knows more then I so maybe He can?
I built a "Big Woody" yesterday to try it out on a 17" monitor and it worked but the fresnel I used (or maybe the dimensions of the box) is rong so I failed dot get sharpness :-(
The picture was very faint (it was not dark enough in the room but I still can se that I need more brightness) so lets hope that You or Scot_lad or I get lucky 🙂
A monitor can pack a nasty punch so be carefull but You now that of corse.
I´m thinking, there are transistors whitch can take a lot of highvoltage and current so maybee an custome amplifier hocked up between the electronics and the CRT is posible . . . ?
By for now
Good luck MarcDM ! 🙂
I have not heard from my friend so I can not help You for the moment but I think Scot_lad knows more then I so maybe He can?
I built a "Big Woody" yesterday to try it out on a 17" monitor and it worked but the fresnel I used (or maybe the dimensions of the box) is rong so I failed dot get sharpness :-(
The picture was very faint (it was not dark enough in the room but I still can se that I need more brightness) so lets hope that You or Scot_lad or I get lucky 🙂
A monitor can pack a nasty punch so be carefull but You now that of corse.
I´m thinking, there are transistors whitch can take a lot of highvoltage and current so maybee an custome amplifier hocked up between the electronics and the CRT is posible . . . ?
By for now
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