never mind, thanks anyhow for trying to help...



Is it possible to mod this to use it for testing leds? 3.3V, 5V and 12V just do not do it for any leds I want to test, so how would I mod it, to get the voltage I need? Is it possible, or practical?

I just don't want to pay the bucks for a real DC power supply, adjustable and all that. Even used ones are rather expensive.

Heres one by Johnny Mac. I'm not sure if it will be helpful or not.

Convert it to a benchtop power supply, then use those 3 pot CC/CV converters to step down the voltage to the correct levels you want.

There are TONS of howto’s on just this subject

Discussion on why the outputs need some sort of dummy load for proper regulation

Another great howto w/ faqs on the subject


After reading that forum link, it says what I already thought, don't do it, use the right tool for the job. Buy an adjustable DC power supply. They are right. I was just shortcutting, as usual. I would have to work it to get adjustable voltage and adjustable amperage and after all that, it would probably be as much as buying the proper bench PS. I think I will trash it and stick to a couple batteries, LOL.

why…it will work just fine if you do it right…if it is capable of regulation for computers it will be more than ample for testing LED emitters

Sure…it takes some work to ensure proper regulation but it’s not like you are going to be operating surgical equipment or something that is mission critical, it will be more than ample for what you need it for…even be able to provide regulated 12vdc for your nitecore charger amongst other things

But it’s your call…as for me I know they work just fine

A PC PSU is not bad for LED testing. It can provide tens of amps and also has a lot of safety features so you really can’t kill it. It’s just too robust.

A split second short from one of the three power rails to ground will immediately shut it down, so no need to be concerned about melting wires or fires.

3.3V is perfect for checking XM-L/2, XP-G2, and the 5.0V rails is great for MT-G2 and SST-90.

5.0V will pretty much kill an XM-L2 or an XP-G2 instantly though.

Well, you gave me the link to that forum thread!

Quote "I don't like these builds either, I'd avoid using a supply without current limiting for a project. These ATX supplies are great for what they are, but they are capable of far too much power/current output for general lab use. If you want a 'zero budget' supply for hobby projects I'd rather see you use some old wall warts in a case as they're not capable of this sort of current output which can easily destroy boards and explode parts." Unquote


Quote "If you are just starting out an ATX power supply is about the worst thing you could use because of all the issues it brings with it.
First there is the safety issue, unless you are working with high power equipment, you don't need any voltages over 3A most of the time. Connecting a 20A+ supply to something like a micro powered project using 300ma can be a costly mistake. The other reason not to do it is switching supplies can produce a fair bit of noise in the power itself, and that isn't something you want to have when starting out because it can cause things like an MCU to reset itself and you will spend hours trying to figure out why. For prototyping stuff and projects you really should try to use linear power supplies , the output is nearly perfect DC power and the cost isn't anything huge. Batteries. Yes , the best possible DC power source and often overlooked by many. Yes they can run down, and the alkaline type are throw away items, but lithium rechargeable are really affordable and chargers are too. Powering a circuit from a lithium battery pack is a lot safer, easier, and a cleaner form of power than anything you can power off the AC mains. You can power things like arduino off a lithium pack for hours and hours without needing a charge." Unquote.

Kind of sounds like it's a bad idea, Yes? No?

Using the PSU to directly power the load is, yes, probably a Bad Idea. So don't do it that way. Modifying the PSU to give adjustable voltages on the various rails would be, if not impossible because of the various nonstandard designs of these things, very complex.

Just use the 12V rail to power an offboard DC-DC converter between the PSU and the load being tested. Some are ultra cheap and no-frills offering adjustable voltage only and a current limit of 2-3A, some are fancy and more expensive with independent adjustments for both voltage & current and also with onboard volt/amp digital displays. Search Ebay/Tmart/wherever for 'DC-DC converter' and go nuts.

I use this kind of DC-DC CC/CV converter a display built in…but I started with the non-display having 3 pot DC-DC CC/CV converter…used the small .36” volts display to show the volts leaving the output.

12vdc in, I can adjust it down to whatever voltage and fixed max current flow I want…(well below 12vdc since the module is a buck converter)

Also, with a jack that will fit into your Nitecore charger the ATX powersupply on 12vdc out make a VERY good external powersupply (in case I haven’t mentioned it before)

I also have an old busted 19vdc 7.2A laptop powersupply I use for when I need more than 12vdc (to charge 13.8vdc or higher into a lead acid battery)

I think by the time I "bought" all the extras and then made a trip to Radio Shack for all the different connectors, I probably can just buy a new DC PS for $50 and leave it at that. In fact, knowing me, by the time I got done, I would have lots more invested in a PS I really wouldn't be happy with... much like I do with the lights.Frown

Thanks for all the ideas though. It goes back to "not my area of expertise" and probably best left to someone with the knowledge. It's great to think about it, but mostly out of my league in building it.

Want me to mod it for you sir?

Just came across this too…no need to mod it…plug and play
Don’t let the name fool you

Even a nifty acrylic case