Only one PSU into RGB projector.

[Steve Milani]

Hi guys

First of all I apologize if I written into wrong section...
Well...

From an old desktop PC I took its PSU still 100% working.

I removed all unnecessary wires and I left only those for:
+12V/18A (yellow wires)
+5V/30A (red wires)
GND (black wires)

I thought this way I can save more room inside a future projector and so to build a smaller case.
But... Before I do a bullshit.... better ask to experts...

May it to be useful used as a unique PSU into RGB projector, or it is not advisable/safe???

Any advice welcome.

Thanks!

[andy_con]

http://www.photonlexicon.com/forums/...Power-Supplies

[Steve Milani]

Oooopsss!
Thanks Andy.

I apologize...
I had not seen the old thread...
My fault.

[Steve Milani]

Ok guys... I read all past posts...
But...
What I would like to know is: may I use a desktop PC PSU for give the power to laser modules only (5 or 12V)? (not for scanners).
Available answers:
1) Yes, you can do safely.
2) Ummhhh... could be a risk...
3) Better then noting... you could ALSO use it.
4) Absolutely NOT! It is highly dangerous for laser modules.

Thanks in advance for any answer or advice.

[massivesound]

I have tried to use computer power supplies with some success as laser power supplies as well as power supplies for driving an LED wall that I built. If you get the right one they can be a great way to get several voltages (at very high currents) from a single supply. They also generally have very low ripple voltage since computer components are pretty sensitive (but it never hurts to check). I am fortunate in that I can get samples of power supplies from lots of manufacturers that are destined to be scrapped so I can test them out until I find one that works for an application. Some of them are really tricky with loading. Some want you to have some amount of load all the time on the 5v, 3.3v, and/or 12v bus, so you'd have to put a power resistor on those busses just to sink some power in addition to the power that you need. This is not a good thing in a laser projector for several reasons. Other power supplies have trouble with load that is too light or quick modulation (computers don't have loads that require large current fluctuations at kHz frequencies). The ones I'm using for the LED wall are some of the more solid ones and they don't like it if I run a strobe pattern on the whole wall (no load to full load at 50Hz or so). One way to solve the modulation issue is with extra capacitance on the PSU output. Here's my advice: Don't buy a computer power supply just for the laser. They're too expensive. If you have them laying around that's a different story. Test whatever PSU you're going to use on the bench before you start drilling holes for it in your projector. Also keep in mind that the outputs of ATX power supplies are NOT isolated from the input/ground, so you can't connect two power supplies in series to make a bipolar (+/-) supply.

[Steve Milani]

Thanks *massivesound*

I think I understood you are advising me about NOT to use my old, but fully working, ATX power supply....

Holy cow... I've worked for to "clean up" it from all wiring of unuseful voltages (-5V; -12V; +3.3V; +5V"SB").... and now.... I can not use it.... It will go into dump
I would cry.... (joke)

I really hoped to use it for powering red, green and blue modules (not for scanners!). This way I would have saved a lot of space inside the projector case....
It would have been too good to be true...

Alright... Be patient...

To me, this will be another little brick in the huge wall of knowledge... (Gosh!... How much ignorant I'm yet!)

Thanks anyway for your kind advices.

Steve

[massivesound]

All I was saying is to be sure and test it thoroughly before you use it in a projector. Make sure it can handle light load (or no load) and make sure it can handle modulation at full power. Some of them work fine, some don't.

[RGbee]

Hey Steve,
I'm driving all three lasers in mine from a quaddrive, so i only need one psu (+ one for the scanners)
I've had no issues so far

[andy_con]

I just picked up some great psu's off ebay, 5v 15amp and 12v3amp

[steve-o]

Anybody know of a supply that will provide 5V @ about 10A as well as +15V @ 2-3A and -15V @ 2-3A?
I don't know if such an animal exists.. can't find one .. yet ..