Running the XJ-A140 With Missing Diodes

[krazer]

The strings are driven by a current source, which puts out ~1.5amps per string (each string is 6 diodes, there are 4 strings). The catch is that the projector will shut down if your load does not drop between 20v and 30v, so you need to add resistors to make sure that your load drops a suitable amount of voltage. I would expect ~2ohms will work in your case, possibly up to 5 may be needed. I am not sure if you can get away with running 2 outputs in parallel to run your LED at higher currents, in theory it should be possible but I have not tried it. Also be sure that you do not cut off the temp sense resistors, or let any of the board short out to the heatsink.

[kobra000]

Krazer

oe question when you use the ~symbol..are you implying negative voltage and amperage?..if so how does this change my goals?

[taggalucci]

Krazer

oe question when you use the ~symbol..are you implying negative voltage and amperage?..if so how does this change my goals?

I think he means "about" 2 Ohms.

[krazer]

That is correct, I use ~ to mean 'about', by ~1.5 amps I mean it puts out between 1 and 1.7 amps

[kobra000]

ok cool thats the optimal current range suggested by the guys that have worked with these things (the led ihave) on youtube..so i wont have to tie anything in parallel which is a relief ..now i just gotta figure out how to get the voltage between 18 and 20 volts and i think i got the thing Licked.a friend of mine, Caleb aka boldsword,said id have to use resisters to dummy load the other stations so the red led will turn on.so im gonna have to hit up Jameco or Digikey....

so just to verify a 5-24 ohm power resistor should be sufficient enough to trick the PWS into thinking that there are lasers installed? what style of resistor should i use? through hole,surface mount? turret? wire?..what power rating and tolerance?


thanks guys the information is greatly greatly appreciated.

thanks

Keith.

[kobra000]

oh i forgot to ask...on the ribbon cable..exactly where the laser diode solders in the two little holes where the legs of the laser diode pass through the ribbon cable?,does anyone know which side is positive and which side is negative? like left hole + and right
hole -?..(just as example) hmm 1.5 amps per string...does that mean that 1 single laser diode takes 1.5 amps? or is it balanced out (ran in series or parallel i dont know Which) among the 6 diodes in the string? each laser diode receiving a portion of the 1.5amp load?... (then we are talking miliamps right?)

I was told to use a "Clean" power source,im assuming this means something with low AC ripple,would the projectors power source be considered be a "clean" PWS? (i would have to assume so with all the electronics inside it.)

I firmly believe that the projector power source will operate this LED..but boy is it starting to turn into a pain in the butt!

thanks for ya'll help and advice.greatly appreciated.

thanks

keith.

PS i found this data on a 1w 445nm Blue laser diode on ebay and was wondering if anyone could verify its accuracy?

445nm 1W Blue Laser Diode extracted from DLP projector

Wavelength: 445nm
Output Power: 1000mW
Voltage: 3.7-4.5V DC
Threshold current: 200mA........................not sure what this means
Operating current max: 1400mA................in other words 1.4 amp right? i was told 1000miliamps = 1 amp.
Operating temperature max: 55 °C
Life time: >20000 h
Package: TO18 5.6mm

[kobra000]

in the beginning the OP said not to use wire-wound or thick film resistors..whats that leave us?.what other kinds are there?...cause i picked these out to use
http://www.mouser.com/ProductDetail/Bourns/PWR221T-30-20R0F/?qs=sGAEpiMZZMtlubZbdhIBIPNKsuXHpjQqcnCYgagjWVU%3d
but they are thick film resistors...already bought them too.

if these are unsuitable..what other options are there?..does anyone have a link to ceramic resistors?

also the OP said "*This also means that you can remove an entire string, and replace it with a simple resistor." does this mean i can just cut the 6 stations off any loop/string i want and connect the whole string/loop (all six stations) to a single resistor? how big would that resistor have to be? something tells me it would be pretty big.
also

can i use a variable resistor? was told a volume switch off an old stereo might suffice. i figured it will let me dial in the appropriate amount of resistance without having to buy like 10,20,and 30 ohm resistors and X a pop for X many and once i hit the right resistance i just lock the dial out or remove the knob or something. if i did use a variable resistor what should the minimum and maximum resistance be? like dont go below 15ohms or it will let burn and dont go above say 30ohms (the higher the number the more resistance which means the hotter it will get right?)

also the OP said the PSU can go as low as 20v...what about 18v at 1.5 amp? (i know this is the amperage output of 1 string/loop and i went back and read through the posts and folks have said the array works at 32v.
I tried to verify this but every time i go and hook one of my FlexPCB up to the projector it gives me a temp alarm and does nothing but blink the orange led,though the temp sensors are installed the white one and the small 10k ones,it wont do anything but blink an orange light.what do i do to clear this? heat up the Flexpcb with a hair dryer to simulate thermal load in hopes it tricks the thermal sensors into thinking the lasers are on?)

think anything bad would happen if i were to short all 3 temp sensors just for testing purposes?

ok so if its for a fact that the array runs at 32v with 1.5amp per string (for a total of 6 amps 1.5x4=6) wouldn't an led like this sufficiently duplicate the load required by the LD array? see below

http://www.dealextreme.com/p/50w-400...e-32-36v-66382

its a 32v 1.75 amp LED at 4,000 lumens..or does the amps need to be higher to successfully dupe the load? (if so we are probably talking 8,000-12,000 lumens then! something like this probably see below)

http://www.dealextreme.com/p/prime-1...re-white-42806

its 100 watts 8,000 lumen at 32-36v @3500ma (or 3.5amp right?) closest thing i can find to 6 amps ) if that is indeed the max amperage of the Laser diode array while in use.

Here is one that actually goes over our power requirements of presumably 32v @ 6 amp max see below

http://www.vanqled.com/Eng/ProductDetail.aspx?id=281

its a 300watt 32-36v @7000ma 22,000+ lumen LED..but i think wed need a heatsink the size of a V8 to help cool the thing or even liquid cooling system.probably burn out the DLP chip with its brightness..dont know what lumens the lasers are rated at but id bet money this would out do them by a few miles.

those looking for very high output blue leds might be interested in this..see below

http://www.vanqled.com/Eng/ProductDetail.aspx?id=283

Name: Blue 30W LED Grow Light

Chip QTY: 30PCS high lumen chips

Drive current: 1750mA (typical) .....................basically 1.7 amp right?

Voltage: 12-22V (@1750mA)

Radiant Flux: 9100mW(BLUE)

Wavelength: 450nm (customization)...would 5nm over 445nm be bad?

no clue what this does in lumens but @30watt its gotta be alot.

is there anything saying we cant use some buck up transformers or voltage regulators to get the leds going? (if you wish to use leds,that is)


everyone have a nice week

Keith.

if anyone has anything they'd like to share please contact me at kbr5038572@aim.com its easier to respond to messages there.

[kobra000]

oh just wanted to toss this out there cause i just found it...never seen one like this before


a 60watt 1000 lumen 470nm BLUE led 32-36v @ 2.1a

http://www.dealextreme.com/p/60w-470...e-30-36v-54395

for those who would like to experiment with BLUE leds rather than white leds...and if you really want some power

http://www.alibaba.com/product-gs/42...ower_blue.html

100watt 470nm 30-36v @3500ma 2000-2500 lumen BLUE led.

[kobra000]

Ive been doing some math today trying to figure out what the individual voltage load for each LD station is.......if its for a fact that 32v is the LD arrays operating voltage with a presumably 1.5amp per string for a total of 6 amps (1.5x4=6)
then we would take 32volts divided by 4 strings equals 8 then further divided 8 between the 6 individual LD stations and i get 1.3 (to be technical 1.3333333333333333 or 0.75 if i do it the other way around)
so if my math isnt off this is telling me that each ld is getting 1.3 volts and 0.25 amps (less than a miliamp? 1.5amp divided by 6 stations per string.)

does this sound right to anyone? im not the best with math ill freely admit that.


Keith

[kobra000]

wow this thread has all but died.