Running the XJ-A140 With Missing Diodes

[rhd]

You know, that's not the craziest idea in the world - there might be some chance of that type of approach working:

Theses are 8mm, 3.4V, and 300mA:
http://www.ebay.com/itm/30-PCs-1W-8m...ht_3769wt_1163

So they might actually fit reasonably well in the original diode positions.

The original ribbon cable is going to be no good though, because series wiring these LEDs would overload them with current. I *think* these LEDs would work in two parallel lines of 3 series LEDs. Running that config at spec would imply current of 600mA, and about 10V dropped. If some basic diodes were added to the circuit to drop another ~10V, I think the projector would behave just fine without tripping a temp alarm.

24 blue LEDs might be easier to focus than 4 blue emitter plates. I'm not suggesting the output would be anywhere near as bright as the laser diodes, but it might actually *work* to some degree.

[kobra000]

my freind Caleb made a great diagram showing polarity,im gonna post just for reference.

[kobra000]

here is a picture or two of my Frankenstein creation..forgive the clarity its taken by an ages old webcam.

[kobra000]

you think so? i was just farting around..i half expected them to explode,but it was really surprising that they didnt!!..i ran them with no resistor and i know your supposed to use a resistor when running leds in series,but i wanted to see what just the leds alone would do.i had to replace 3 out of the string today cause 1 was red for some reason and another 2 were not working. (funny thing i found is a fluke meter set to tone/continuity test will actually light them up,never encountered that before!) i couldnt tell you the specs on the LEDS if my life depended on it,just outta some 5 dollar work light i got from a salvage tool store. im going to try and use some resistors to drop the voltage alittle more and see what i get..ive spent most of the day harvesting diodes and resistors from old dvd players,a playstation1 power board,and some old old stereos,i was told 15 to 20ohms is the range i want to be in so when i find one of them or close to it im going to try it out once i figure out how to hook it up,i was told you can install a resistor on LEDS on either the positive or negative side but im not sure exactly how to do that and fit it to the Flex cable..(replace 1 led with a resistor and solder to the positive side? or just solder it to two neg led terminals?).

lol sometimes i find the best way to figure something out is set out with the heartfelt intention of messing it up! lol.

[kobra000]

ok to find out what the specs of these LEDS are i did a resistance test and they show up as 1.432 Kohms...now is that far too much or far to low for the the projo to be happy.? cause when it comes to ohms,Kohms and Mohms..ill admit i get rather confused.

[rhd]

ok to find out what the specs of these LEDS are i did a resistance test and they show up as 1.432 Kohms...now is that far too much or far to low for the the projo to be happy.? cause when it comes to ohms,Kohms and Mohms..ill admit i get rather confused.

Resistance is irrelevant. Maximum current and Vf per diode are what matter.

[kobra000]

hmmm that means that these leds aren't even a drop in the bucket then. meh just an experiment.

[kobra000]

i found this .pdf file which really goes in depth into collimation and how it works and what its for and all....really helped answer alot of my questions.

http://www.reflexite.com/tl_files/En...nel-Lenses.pdf

it says that a fresnal can be a pretty effective collimator,i got tons of those laying around (old DIY Projector idea leftovers) along with fresnals from the insides of LCD screens a plenty..eh worth a shot right...though i dont think plastic ones are going to do well..most likely glass will be needed.

hope you guys enjoy the .pdf file.


RDH did you say that the focal point of the collimator lens would have be very wide or vary narrow?

[kobra000]

i just wanted to ask something real quick
i was wondering what do you all think about using a automotive LED headlights? ive seen others with DIY or scratch built projectors use car headlights with fantastic results..and ive noticed alot of LED headlights out there.Now somewhere i read that the light from a car headlight is already collimated via built in collimating lenses think it would be easy enough to externally power them.(12v dc easy),they obviously have very high output (2000,4000,6000,lumens) with an easy to choose color temp index (4300k-10,000k no guess work involved its on the package) they last a hell of a long time,(2000 to 20,000hours) and they obviously run alot cooler , from all the images ive seen on google search there is no heatsink needed.(of course i could be wrong about this i realize that)
the blue headlights have really gotten my attention,especially the type T10 wedge style,to me they have the following pros
small
cheap (depends on how deep your pockets are)
high output
high color intensity
built in protection
internal/built in collimation
safe to use with plastic lenses. (according to retailers)

only thing is they dont approach the Nm range of 445nm, you can get them with a noticeable blue hue or tint,but not the type of deep blue we need,but i dont think that is exactly a huge problem (lens,filter, colored prism/crystal ect ect RDH i remember what you said about lenses and filters,this is different.) and i think it would be a huge PITA trying to run them off the Projector PSU,not without some serious and very involving custom DC-DC voltage regulator work. but for an an external solution,i dont know,at $5-$25 a pair,they seem worth a shot to me.

just spitballing here.

[reuterric]

hello. I've got a xj-A130. but it lacks the laser module with flex cable. the device will not start (temp + lamp). can someone send such a flex cable to germany. or anyone knows the pinout. a good photo of the front and back would be very good.thanks.