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Computer PSU to power LDs?

Lew8

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A pc PSU is all i have ever used!
The driver i use goes up to 500ma which is fine for most laser projects i do and it has a wide voltage input rage of something like 4.5-20v which means it is just fine to run it from the 12 power rail of even a 100 watt PSU.
If you want to mod one of these PSU's you dont even need to take the cover off.... other than for a good look around :). there are loads of tutorials on how to do this but usually you can just connect acd drive as a test load and add a N.O switch between the ground rail and the grey/green pwr on rail. this will fire up the PSU, its fan and the cd drive. now all you need to do is get a highish power voltage regulator with an anti current spike capacitor accross the rails over a few hundred uF should do it. then take the output of the voltage regulator and connect it to one of the small ld drivers such as the rckstr or dr lava driver and there you go. :)
 

BShanahan14rulz

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Documentation

Best I can see is that the grey wire on pin 13 (24 on your diagram) is related to turning the PSU on. I can't tell, though, if it only requires a simple short to ground or what. Normally it is floating at 4 or 5V, so I can only assume/guess to short it to a black wire and see if it does anything.

Another diagram on the same page shows the PSon pin going to the power logic part of the board. That could mean anything from advanced power management to fancy word for on/off button.

So if you are fine with possibly frying your PSU, I'd say give that a try.
 

Meatball

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PC PSU's are hardly a good choice for these things. Often they require some minimal load to function properly, and drving a laser diode is not likely to meet that.

These switchting power supplies are designed to work very welll with the intended loads connected, but sometimes can do strange things ohterwise.. be wary!
You're very correct! Though, what can be done, is solder a single 10 ohm (20 watt) resistor across the 12V rails. This is usually enough load to let the supply run, even without a big ol' laser diode hooked up.
 




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