I did a quick search on here and didn’t see anything…but I know I can’t be the first person to have thought of this.
My computer nerd came out today. I was looking for a power supply. I have one for the track and DCC set up. But I wanted an alternate power supply for other things like lights and random things.
So I’m using an old PC power supply. The best part? It has drops for 12v, 5v and 3.5v. And a ton of them. Maybe a half a dozen of each? And they are free. You can find an old pc anywhere and tear it out. It’s got a huge amount of amps that will let me run more than enough LED’s and regular bulbs. It also has a built in cooling fan! Pretty slick. I’m sure it’s overkill for most. But it’s going to work perfect for what I need it for and allows me to not have to run resistors on some of the bigger runs of LED’s which is nice.
Hard to beat free and I like having options so I thought I’d pass along the thought. There are some tricks to get them to work, so you have to pay attention there. But there are How To’s all over the net. I’m no genius and was able to make it work and it’s been a nice addition to the layout!
I remember others on here who have mentioned using computer power supplies to power supplimental things like lighting and turnouts on their layout. I’m just curious how robust they are in the long haul and whether the current is “filtered”, like it is on a good MRC power pack? Besides aging hard drives and software obsolescence, power supplies “seem” to be other weak link to a computer’s longevity.
Yes most important thing is multiple runs with fuse - do NOT runt he 12V output of a PC power supply directly around the layout. Even a fairly modest one with only 10 amps on the 12V side (and a typical 500W one will be more like 40 amps on the 12V lines!) is 120 watts of heat in a short - definitely enough heat to melt and/or burn things.
The safety issue of opening them up can be mitgated by the device I posted in a previous power supply thread (on the main section, unless it got moved here) from SparkFun, which is a board that plugs in to the power supply connector and had multiple fuses plus a button to turn on the power supply. So you cna connect one, WITH FUSES, without having to open it up and make modifications. Those big capacitors in the power supply can bite, hard, even if the power cord is disconnected.
It is a perfectly viable alternative - just be sure to do it safely. If I use a PC power supply, I may fancy it up a bit and mount it in another small case with terminals on the outside, or I may just go for those smaller block power supplies common on eBay and Amazon, switchers like a computer supply but just a couple of terminals to hook things up, not wires flying all over the place. A modular type PC supply can get around that, but then you are paying extra for a feature that makes for wire neatness in a PC case which may or may not be a concern buried under your model railroad.