| PaulH_1980 |
Hello. This is only my third post ot the board. I started out with interest in this project by seeing those 150" TV kits on ebay and started researching on the net. I made a lame magnifier projector for my monitor.
I have been reading the boards for awhile now, and setup an account here a little while ago so I could post about a thread I saw. I have finally ordered my pieces for my setup off ebay and they arrived today. I was so excited I tried to set it all up only to be very, very disappointed by what I am hoping is just a major problem and not my final results.
I am using a Dukane 4003 OHP and a 3M 6400 LCD Panel. I hooked up my stuff and the panel looks great when you are looking at it on the overhead. But the problem is what is projected on the wall completely sucks.
I have noticed it seems like the majority of the picture you can see [ projected on the wall] is the part from the LCD that is on the bottom 2-3" of the OHP glass. [ The part that faces the projection wall, not away. ] The rest of the picture seems to be blacked out, or almost completely dark, I can see a little of the top. I thought this sounded like what I have read here about the fresnel lens being installed backwards in the OHP and took it out to see, but the side labeled "UP" is up, and I have tried flipping it both ways to see if it makes a difference. I have also tried adjusting the brightness of the LCD & OHP with no luck. I can clearly see the bottom half of the screen but the middle area fades to black.
I noticed I had a problem with this also when I was testing my OHP with a film negative. It seemed like it only showed up on the wall in focus [or viewable] when it was on the bottom section of the glass on the OHP. I'm thinking something must be wrong with the OHP because how would a teacher project a full page transparency if this was how the OHP normally worked.
I have tried searching the forum for info on this but have not been able to find anything specific. I'm kinda disappointed as I was looking forward to playing with my new toys but alas, it is not viewable. If anyone has experienced this problem or has any ideas of things I could try to fix it I would greatly appreciate the input. I have been super impressed with the work people in the forum have been doing, and would equate it to the old school hackers that built their own PC's as they could not afford to buy one for a hundred thousand dollars. I'm hoping I can get past this set back and work on improving my design for a final projector I would like to build. Thanks to all for the inspiration, and ideas...
-Paul- |
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| Hezz |
Paul,
I may be wrong but it sounds like your light element is out of alignment. A OHP projector needs to have the lower light and reflection mechanism properly aligned.
Hezz |
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| li_gangyi |
| Try the OHP without the LCD and se if there's black "hole" if there is...it's thr OHP...if there is non...it's the LCD...for the OHP...you might wanna see if you got the reflector properly adjusted...sometimes there is a knob for u to switch between 2 lamps...if the knob is a bit off u might get that...or it might be the "coulr" control... |
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| PaulH_1980 |
Thanks for the advice...
Hezz - I think you are right. It seems like the bulb is possibly not aligned properly and light is being wasted in my projector. I have made images of what I have found to be a possible problem in my OHP.
li_gangyi - I took your advice and used the OHP without the LCD. It projected ok onto the wall. It was hard to say for sure without something to focus so I tried it with a film negative, and was able to focus it ok when the negative was over the "sweet spot" on the glass. The "Knob" you mention really makes me think this may be the root of my problem. In the Dukane 4003 there is actually a lever you can slide back and forth to switch between bulbs, except in the one I purchased it appears this has broken off. I do not have a reference as to how it should be so I can't say for sure if this has thrown it off alignment.
I have been messing around with the OHP since my last post trying to figure out what is wrong with it and have made some images to show people what I think is happening. It seems as though the bulb is located behind a metal panel in the OHP which looks like it blocks 2/3's of the bulb, and seems like it would be wasting light. I'm not sure if this is just a crappy design, if my OHP bulb is out of aligment, or if there is actually some purpose as to why this is setup like this. I would be interested to hear from others that have a Dukane 4003, to see what theirs looks like.
Because of the fact that the light seems to be blocked I would guess that the light that does get through from the top 1/3 of the light is probably hitting the highest point on the reflective mirror, and then reflecting through only the bottom portion of the glass on my OHP. [The portion closet to the wall i'm projecting onto] It seems like this would create the type of "sweet spot" I was referring to. Because of this I can only really get a projection through the LCD if it is over the exact spot.
I'm thinking it could benefit my projection, to take a hack saw and cut out a square section in the metal panel that is blocking my light bulb so that the entire focus of the light falls onto the surface of the reflective mirror. I'm wondering what others think of this, and if it would be a wise idea or not as I have paid about $50 for my OHP.
I have also noticed that a lot of ambient light gets projected through my LCD directly up to the ceiling, into an area that is brighter that the picture I can project onto the wall. I'm not sure of this is because of the sweet spot or because something else may be out of alignment. It would be nice if I could direct that light into the triplet lens to improve the image quality of my projector. This has been shown in my third picture.
Thanks to all for the input, i'm hoping to get something worked out with this so I can get some initial tests done with my projector. Although if this continues to pose more problems for me I will probably be looking into stripping the OHP down for parts and putting it into a straight projector enclosure design as alot of people have done to make the best use of my equipment. Thanks again for the help.
-Paul- |
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| li_gangyi |
| I'll bet it's the lever...well you already cut the thing up so wad the hell...abit of stray light shooting up is normal...as for the "sweet spot" thingy it sounds as you've misaligned optics....hmmm...can you shift the thing with out the broken lever?? |
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| buckster |
Let me start by saying I have never looked inside a 4003. I have a 3M 9550, with a mirror like you illustration. 1st off I can see no reason for plate #2 cutting accross the middle of the bulb I'm 99% sure this is wrong, check to see if plate #1 can be adjusted up or down, if not then plate #2 is in wrong. In fact it looks to me like the mirror angle is determined by the bottom of plate #2. Getting plate #2 back where it belongs might change the angle of the mirror which would focus the light back to the center of the fresnel. This could be the reason so much light is missing the triplet.
Also your illustration shows the light out put as multicolored, if you are getting multicolored light on the screen or the stage, it indicates that the light source not the proper focal length from the fresnel.
Hope this helps:) |
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| buckster |
I was looking at dukane overhead on ebay and I noticed that the legs fold up, is this the case with the 4003? If it is , do you have the legs extended, It seems I read about another person who had a problem like this, It wouldn't project correctly because the mirror was not in the proper place. though, I can't see why the projector would even turn on that way?
Anyway... |
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| ksavage68 |
I have the dukane 4003 OHP and you need to open the bottom of it and unfold the doors so it will sit up on those legs. then be sure the mirror assembly falls down through the bottom all the way and make sure the power cord is pulled out completely from the projector bottom. Then the light can get to the mirror assembly properly. You should then see perfect image. hope that helps. :)
Keith |
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| PaulH_1980 |
Man I feel stupid... After all the troubleshooting and poking around I did, I was missing the most obvious solution. Thanks to all for the suggestions and help. It was in fact that I had the legs folded in on the projector that I was unable to project a viewable image. Well actually you could see my image, although it was horrible. I didn't even know this was the case, as I recieved no manual with the OHP when I bought it, just the carrying case.
But now I have a beautiful picture coming through, I'm so happy that this is starting to work out. Thanks to all once again for the help. I am attaching a picture of my results so people can see their trouble-shooting advice in action.
I'm using the Dukane 4003 OHP.
The 410 watt FXL that came with.
A 3M 6400 LCD Panel.
Dingy wall in the living room.
The first picture gives an idea of the size of the screen [8' feet by 6' feet]
The second is me celebrating finally being able to watch movies on my setup:
Thanks once again to everyone for the good advice and help. I will be keeping up with this forum, and also updating people with my project. This board has been a great source of inspiration for what I would like to do with this in the future. Thanks again !!!
-Paul- |
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