I was wandering has anyone ever tried using a computer power supply for powering things, summary of what I need → ten stationary decoders (at 300mA each) would add up to 3Amps… the tortoises at 16mA add another .16 A… total is 3.16 Amps draw max.
Now has anyone ever tried using the 12volt leads from a computer power supply I would think with the size of the power supplies for even old computers there would be enuff amperage available.
Would use happen to know what kinda amperage the 12volt leads would put out in the way of amperage?
Don’t know about the computor power supply but, Your tortoise machines
should get their power from an old auxillary power pack or have their own pack.
Not good to connect the track power to operate the Tortoises cause it can create
voltage drops in the system. An average system can use a pack output of 5 amps.
The bad news. I tried it and couldn’t get it to work. A PC power supply won’t power iup without a load. Even using the load suggested in the link above, I was unable to get it to come up.
Yes, a computer power will work for the building and light poles. I have been using one for about 3 months now and have had no problems with it. I have not tried it on my switch machines, (Atlas) I use an old train power supply for that, I tried using the AC side of the power supply that I run my train with, but when I threw a turnout switch, the train would slow way down. I use the computer power supply for all the lights on my HO layout. Hope this helps. Mike
I use a computer power supply for all the accesories on my layout. The 5v side of the power supply I believe is 5 amps. and the 12 side is 1 amp. I think this is what it said but I can’t remember for sure.
You do need to make sure there is a load on it how ever. Using a resistor works but also using lights in a building will also work. For example at one of the clubs i belong to we used the computer power supply to power the 24+ tortoises and all the lights around the main yard area (15 track yard + two engine facilities) We used the passenger platform lights as the “load” that is required for the power supply.
You probably have a newer supply with the sense lead.
On most of them you connect the brown and orange wires. The 5 volt load resistor can be in the 10 - 25 ohm range. I would suggest that you try loads as high as 100 ohms to save some power. You may need a load on the 12 volt supply too.
ok guys you probably thought this was too simple so here it comes time for the real novice but adventurous question…how exactley do you hook up a load with a resistor [:I]
The resistor hooks up between one of the 5V wires and one of the common wires. Which one doesn’t really matter, they all connect to the same point internally. I actually opened up my power supply and used a pair for the resistor and a different pair for the actual power output leads (I put binding posts ont he case of the supply). Note the resistor has to be a high power one, usually the ‘sandbar’ type - a typical 1/2 watt resistor will just melt. The PC supply I had needed a pretty hefty load on the 5V - 100 ohms did not cut it. I experimented with clip leads before gutting the supply to find a value that worked - with insufficient load the 12V output was WAY low and the 5V approached 6 volts. The 12V being low isn’t a problem -Tortoises and light bulbs will be just fine if down a volt - but the 5V being that high could be death to electronics expecting a max 5V input. I ended up actualy using two resistors to get the value I needed, don’t recall what value they are off the top of my head - I think two 100 ohm in parallel - 50 ohms actual resistence. While the power supply is still mostly whole - cut off the plugs - connect resistors and measure the voltage and you will find a good value to use.
Also be careful messing around with the power supply. The capacitors in a switching power supply retain their charge for a long time and can give a nasty jolt, even if everythign is unplugged. ANd do not forget to unplug it fromt he power line - especially the newer ATX style supplies, they remain energized even when switched off. PULL THE PLUG! This isn’t really something a complete novice should be messing with.
Try using an AT style power supply for this. They came in OLD computers with the Large keyboard plugs (about the size of your thumb) and with processor speeds below 500Mhz. (500Mhz was the end of the line for these) All new computers use ATX power supplies with small PS2 keyboard plugs. The old AT power supplies had a wired on/off switch with 4 wires going to it. The much older ones don’t have the load sensing that the newer ones have.