Powering a cathode light with PC off

Waynerrr

Waynerrr

Waynerrr

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Joined
27 Feb 2009
Posts
38
Hi there. First post, first question, bear with me. I know very little about case modding (other than some of the stuff I've seen is f'awesome) so this might be a simple question with a simple answer.

How do I power a cathode light inside the PC without powering on the computer itself?

I don't have the motherboard details at the moment as the computer is at work, but I assume there is some power being drawn that I can tap into without turning the PC on? Or, is there another simplar way?
I would obviously need a switch for the light, something I haven't seen (looked for very well) on the site. Links?

Oh, I did a search for an answer and found a few posts that just confused me further to be honest.

Thanks for your help...
 
I doubt you'll be able to get power through the mobo...

One thing you can do is to get a single molex PSU. I haven't seen any for sale in the UK but you can get one here. I hope that's not counted as a competitor mods, as it's a US seller.

It would probably just be easier to mod one into the mains supply. I do not have experience with this so i'm going to stop there. I don't want you to blow yourself up because of my bad advice... :p

I'm sure someone will come along with the know how on how to do this.
 
Absolutely simple, providing you can do a little soldering :)
Take any spare 12v DC adaptor (Lower voltages may work, don't go above this though), and snip through the two black wires. Next, you want an old molex connector off somthing (Or the auction site)- Connect one of your black wires to the yellow wire, & the other to the two black wires.

A couple of words of warning-
1. Please test either test the two wires from the adaptor with a multimeter first to figure out which is + & GND, OR test with a fan or similar first (They run in both directions, & you can't do much damage with them).
2. IIRC most cathodes are going to want closer to 2A, check yours & the adaptor you plan on using first.

-Leezer-
 
mark1: Interesting item, thanks.

I might be able to do as leezer3 suggests with a laptop power supply... Will check power and ampage tomorrow with what I have kicking around at work.

I was hoping it would be simpler :(
 
AC Ryan has detailed specs for their CCFL's and all of them have 12V input inverter.
Same applies probably to all others because it's easier to make required voltage from 12V than still lower voltage.
 
Well the laptop power supply was a bad idea (only one cable at the business end of the adapter). Now I know the type of adapter I need it shouldn't be a problem finding one.
 
I know that some PSU's out there are able to still have power on for the molex or external USB connections even when the computer is turned off. Some PSU's may even have an external molex connection on them too for this purose or testing other devices.

My second PC has an Akasa PaxPower 460W PSU and it is able to do this. Whilst the PC is off, I am able to switch on any cathodes that are connected via molex power connections, or switch on USB powered cathodes.
 
I have a Dual inverter 10" cathodes whicg state on the back 3W. So no where near 2A. It gives 0.16A
Any idea where you get 2A from?
 
On another site I have seen a "USB to IDE & SATA Adapter With Power Adapter" for £12, and the power adapter part of that is basically a single molex plug for hard drives, so you could use that if you think its worth the cost.

PK!
 
I am not sure but on one of my very old psu I seem to remember a molex connector next to the on off switch.

I havent seen one since but it was a very cheap psu that came with a crap £15 case from a shop in the local town.
 
I'm just sort of thinking out loud here, but the connector coming from the PSU to the motherboard (twin black and yellow cables) must be getting power all the time? Can I not feed off this or is the power less than 12v (or doesn't it matter because of the inverter?)?
 
As far as I know that supply isnt on constantly (ie when the computer is off). The only one that is is the purple wire on the main motherboard connector. Don't use try and use that though, as its only a low current 5v supply.

PK!
 
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