Running the XJ-A140 With Missing Diodes

[kobra000]

Reuterric

look at post #158..there is a pretty good picture of an LSA-25 and LSA20 cable (im not sure if the xj-a130 takes either cable cause all i have is 140s that take the LSA-25 cable.) but it only shows one side..there is a pin legend silkscreened on the underside of the board right next to the connector,as for a pinout good luck,data on this these projectors is scarce,but there is a plethora of info and data in the previous posts. even quite a few posts on how to get the projector to come on without the lasers at all (short version is short contact pads 4 and 9 on the c509 and viola,it will run without lasers and allow you to use alternate light sources)
here is another good one (best i can find) of the other opposite side not shown in post 158



good luck and happy experimenting.

Keith.

[kobra000]

im not sure so dont hold it against me if it turns out not to be solid,but i found this list of supplier for replacement laser diode blocks

http://www.casio-intl.com/support/repair/projector/

ive already emailed them and asked for a price list and availability.

[Photonbeam]

I bought some xj a140's to harvest blue lasers when the craze first hit and ended up keeping one projector intact to use as a TV. Now with 6K hrs the DLP chip is showing bad pixels - more and more everyday. It should be a simple matter to pull the diode block and pop it into one of the new laser-less carcasses I have left. I guess they are interchangeable?

[kobra000]

I bought some xj a140's to harvest blue lasers when the craze first hit and ended up keeping one projector intact to use as a TV. Now with 6K hrs the DLP chip is showing bad pixels - more and more everyday. It should be a simple matter to pull the diode block and pop it into one of the new laser-less carcasses I have left. I guess they are interchangeable?

yeah it should be,i mean one x140 is just the same as another...and projectors without their lasers are a dim a dozen these days


Keith.

[LesioQ]

Hi,

I did exactly same thing - my A140 has started to show bad pixels before 100hrs run time, so I got a 235V shell and did a swap
Now I have 2hrs run time WXGA image and a spare A140 to experiment with.

Piotr.K

[reuterric]

hello. can anyone tell what are the components of (highlighted in picture). R or C (values). I want to build my cable since I have none.
It may be that the beamer does not jump when the power consumption of the laser diode has a different value. thank you

[krazer]

Hey Guys -
Sorry again for my lack of input on the thread, but I found some time while digesting thanksgiving dinner to put some thought into this.

per the black things -
I am not exactly sure what the 4 closest to the connector are, I think that they are a zener diodes used to protect the lasers. They are not necessary, and you will be fine omitting them. The only external parts you need are the 2 thermistors that are located away from the connector, you can use a 10k resistor to simulate them. Alternatively, you can use a 10k NTC thermistor (you can get them in a wide variety of packages to fit your needs), and the projector will shut down when the diode blocks gets to about 160F.



Per the previous comments in the thread-
It has been mentioned many times before, but bears repeating again, the electrical issues are a problem that can be solved, the much larger issue has to do with the optics. The reason that the blue lasers were used is that they have a much better beam profile than any LED (and due to the way they are constructed I do not expect that any blue LEDs will be able to rival them any time soon). Because of this, if you try to use a blue LED in place of the diode array you will not get much output, maybe 5W tops out of the projector with the way that the optics are set up currently. There is no reason that you can't get a good working projector using LED's, and getting 1000lumens should be a very attainable goal if not more. The issue is that the green/blue path is set up in a way that requires a very well collimated beam (as would be provided by the lasers) so if you use a LED source most of the light is getting thrown away in the optics.

The solution to this is to make the blue and green optical paths look like the red optical path, luckily I really do not think it would be all that hard to make this work. I think with the way that the optics are done you will be best off using a route like shown below:

(thanks to the original poster, I hope they do not mind my reusing it)

The general idea is that you want to make the beam path for the red/green beams look the same as the path for the red beam. The projector is currently set up with a short focal length in front of the red LED, the pass blue/red, reflect green dicro, then a longish focal length lens, the pass blue, reflect red/green dicro, then a short focal length lens which couples light into the light pipe feeding into the DLP assembly. In the above image I propose we rip out the color wheel, and add 2 more phatlight modules attached on the right side of the picture. One medium focal length lens would need to be added in the blue beam path (luckily, I think that there should be space for it), and the casing modified to allow for 2 more LED/heatsink/tec/short focal length assemblies. The biggest flaw that I see in this design is that as drawn the blue led is going to be sticking out the front of the projector, but I am fairly confident that with a bit of creativity and experimentation we can shorten the beam path enough to cram everything in there.

One obvious mod would be to rotate the pass blue/red, reflect green dicro so that the green module can be mounted where the lasers were, which would help clear up space to fit the blue module in where the color wheel used to be.


As far as getting this system to work electrically, it may be possible to hack the existing driver board to do the job, but we will probably end up using 3 LED drivers (I believe there are bricks available to power the LEDs, or I can whip together a custom one if it comes to it) powered off the main power supply in the projector, and tapping into either using the signals to the color wheel to derive the timing or preferably taping into the red/gree/blue sync lines from the DLP controller.


If you have questions I can try to draw a better picture, but in the mean time I do not think I am going to have time to actually build this for another few months

[kobra000]

Krazer.

cool sorta like i was thinking.but with a recase of the entire projector guts...one question though...when the laser diode array is installed,the 24 lenses that are installed with it..do they diffuse or collimate the laser beams? and then are they diffused or collimated even more so via help from the very first lens in the system? (large first lens at the end of the mirror assembly) im trying to figure out if the beams are contacting the DLP individually or if they are collimated into one large beam..or if they are diffused so much that they act more like fog lights when contacting the DLP.

im still very very curious to stick a blue LED in there and blast everything with like 6000 lumens of blue light..i found a good one on ebay for 35 bucks (4000 lumens @ 1.5 amp 28-36v with the data you told me 1 string should run it nicely)...Im willing to give it a shot just to see what will happen...of course ill post it to show everyone...if it fails it well help the newcomers out alot and save everyone some time trouble and money..(curiosity is such and itch that you just cant help but scratch sometimes) i aslo had the idea of just swapping the red Phatlight out with a white one and firing it up (once i get the diode trick fix to work) and just ya know see what happens..(my ways are not very scientific,i basically just foodle with stuff until it works or blows up..so far that hasn't happened yet! lol... and i got some very interesting,though brief, results with my 24 10MM white led experiment...

since the DLP pulses so many times per second (and there is no color wheel)..what do you think will happen if a white light were put right behind it at the end of the Light tunnel? (of course not too close cause of the heat factor) just bypass the optics completely! or at the very last lens in the system..im not sure how this projector mixes its colors or if it pulses each color a bit brighter than usual in accordance with the DLP color pulse...i assume this takes place so fast it tricks the eyes into seeing all 3 colors at once. reds,greens,blues all where they should be.

Im also very very tempted to see if i can construct my own flexpcb.i figured some copper shielding tape and some self adhesive type of plastic will work if i do them in layers separating each trace and string from the next so they wont short..now the connectors are a real challenge cause they are like 1 or 2mm wide ,well i was thinking of making a simple jig with aluminum and some fine pitch gears...some Fine pitch gears out there their tooth spacing is in the mm range..and i think when ran across that foil it would pretty darn close approximate and cut the spacing of the connectors on the flexcable..I only came up with the idea of a custom FlexCable so one could have a more custom mounting option such as mounting large resistors,diodes or what have you easier..the factory Flexcables are extremely fragile!..ive already broke 4 or 5 in my experiments.(Krazer thanks again for tossing those extra 10 LSA 20's in man,i appreciate the hell out of that!)

also..what about low current capacitors?...i heard in a video on youtube that they can be used to smooth out and regulate voltage an current,...i dont know just an idea.im willing to try anything.. if hamsters best approximated the resistance and voltage drop of those Blue laser diodes hey id use them! lol

I have a theory about the little black things..on both sides of the felxcable there are two large screw holes..but not covered with the brown plastic..they are partially opened to imply contact with the screw head and the heat sink..what if some sort of continuity is ran through the entire aluminum heat sink block itself and these 4 little black things are there as a check system..if one is either open or closed it prevents the signal from returning or returning with an out of wack value and this causes a failure of some type...i dont know just a theory.

hope everyone ate like kings and had a great thanksgiving!

Happy thanksgiving guys

Keith.

[krazer]

The 24 small lenses collimate each of the 2 laser diodes, the composite of 24 laser beams are then focused down onto the phosphor wheel which diffuses them to generate the green, and they go through a piece of textured plastic which diffuses them slightly for the blue section (the final beam for all of the colors is sent through a light pipe which works to homogenize the light so that you get even illumination on the DLP chip).

If you do try using the fat blue LED, I would remove the piece with 8 small mirrors and shine the LED strait into the lens that focuses down onto the phosphor wheel.

If you do put a white light source behind the tunnel you will get a black/white projector, which will work quite well. I would shoot for an LED that has a die which is about the same size (or slightly smaller than) the DLP chip.Alternatively, if you remove the pass blue/red, reflect green dicro and replace the reflect red/green, pass blue with a mirror you could put the white source where the red LED was, using the existing cooling/lenses. Just make sure to get a white that does not have a built in colminating lens, since you will be using the lens that comes with the projector.

Per making a custom flex cable, it is possible but I would not recommend it. The cables are very fragile, but a custom cable will probably be more fragile. I recommend attaching some small wire (I have used 32awg without problems) to the flex pcb and using some epoxy or tape to secure the wires and just tuck it out of the way.

I am not sure where you are going with the caps, I would stick with resistors and LEDs. In particular, I do not think the power supply will like powering them, and you will still need some kind of load to trick it into thinking there are lasers connected.

The black things should definitely not be in electrical contact with the heatsink, you are correct that the ground plane of the flex PCB is in electrical contact with the heatsink/projector chassis, but this is just to prevent electrical interference and does not have any real function that we are concerned with.

[kobra000]

yeah i was going to remove that mirror assy cause i need the room for a big heat sink for the LED..while its in there i dont have hardly enough room unless i do some type of milled up heatsink that will cost way too much

i just thought caps (capacitors) might sub for diodes or transistors better and take whatever juice they are rated at 4.5-5 volts like you said and just buss it off as heat.but i forgot that caps need to discharge before they can charge again..dont know how that one would work....lol except perhaps for a jacobs ladder going up the back lol..

yeah i was spitballing with the custom cable..i was trying to come up with a way i could mount things easier if i made a stronger cable..ive busted too many good flex cables.i dont might something i try down the road.

yep i was going to to do just that take the red PL out and put a white PH right in its place...i figure as long as it has the same power specs the projector should know the difference.
thanks man i appreciate it.

Keith.