wiring... t.y.v.m. Will do that. I'm at a stuck point. All going good except I happened upon a site yelling about NOT using the 10w/10ohm resistor. They suggested something else with car bulbs and such. Dunno what to do.
Either the resistor or the automobile light bulb(s) will work. The point is that for some computer power supplies, you must place a load on the 5V line in order for the power supply to work properly. In a computer, that load is provided by the hard drive and other computer components. When using the power supply apart from a computer, you have to provide the load in the form of a resistor, light bulb, etc. In my own converted PC power supply, I use a resistor. Some people prefer to use light bulbs. Either will work. Here are a few discussion forum threads (from an R/C airplane forum) on the topic of converting a PC power supplies for use as 12V supply: http://www.rcgroups.com/forums/showthread.php?t=368639 http://www.rcgroups.com/forums/showthread.php?t=315179 http://www.rcgroups.com/forums/showthread.php?threadid=55555 http://www.rcgroups.com/forums/showthread.php?threadid=114054 http://www.rcgroups.com/forums/showthread.php?threadid=41161 http://www.flyinggiants.com/forums/fg189/12159-frankenpower-building-12v-power-supply.html In addition, here are some helpful web sites on the same topic: http://web2.murraystate.edu/andy.batts/ps/powersupply.htm http://web2.murraystate.edu/andy.batts/ps/DESIGN_GUIDE.HTM http://www.marcee.org/Articles/PCPowerSupply.htm http://www.extensiontech.net/articles/howto/jb/pstu/ http://reckerclub.tripod.com/id105.html http://homepage.ntlworld.com/fast.electrics/PSU.pdf The R/C airplane guys use PC power supplies as a source of 12V for their battery chargers, so most of the links above make reference to R/C battery charging. But 12V is 12V, no matter what you are connecting to it. - Jeff
wiring... ok, here comes a dumb one. What would I use the -12volt for? And if I hook more than 1 +12v.(yellow) wire to the binding post, does the volts add up and equal +36volts? Or does it stay +12v. no matter how many I hook together? confusing, but strangely i'm having fun.
You probably won't have a use for the -12V line. But there are some applications (and computers are one of them) where both plus and minus voltages are needed. You can also use the +12 and -12 if you need 24V for something. The -12V line usually has a fairly low current rating. You can connect as many +12V yellow wires to the binding post as you want, and you'll still have +12V. Good luck and be careful. Despite the fact that the power supply puts out relatively low voltages, there are some very high voltages internally when the power supply is operating. The internal voltages can be in the hundreds of volts -- potentially lethal -- so don't poke around inside the power supply when it is switched on. - Jeff
As I understand it if you attach something to the black (common) and the -12 you still will have 12 volts, but the Black is now the + lead. (Note: if this is not correct will someone please correct me. Thanks Gary) Furthermore attaching all the yellow leads to the same post should still be just 12 volts. It would or should be like hooking up 3 12 volt batteries in parallel ( + to + to + and - to - to -) same voltage and if the yellow leads come from different sources more amps, but most likely the same amps assuming that all the yellow leads come form the same point in the power supply. Not really sure how a power supply is wired inside. Why not take each yellow lead to its own binding post? That way there will be less wires attached on each post. Gary
Wiring I was thinking about giving a separate binding post for each yellow wire, but I read that sometimes if your going to use more power, that you should have more than one wire attached to the post. I was gonna connect 2 and snip the rest. I'm still trying to find out somewhere in all of the r/c forums and such,.. if the LED i'm hooking up to the +5 volts wire for an on/off light,...is also strong enough to be the "load" that is also required. I also read that another fan installed will work also,.. but I dont know if it still has to be +5 volts, because the fan I am going to use is +12 volts.
Connecting a LED to the 5V line almost certainly will NOT be a large enough load. LEDs draw a tiny amount of current, so little that the power supply is unlikely to see it as a load. Usually, the load must be connected to the 5V line, so a 12V fan connected to the 12V line won't provide the needed load, either. You could try connecting the 12V fan to the 5V line. It won't hurt the fan, and it might be a sufficient load, but I have never tried it. The 12V fan will run fairly slowly when connected to the 5V line, however. - Jeff
Hooking up the sand resistor, as detailed in the links I provide in the how-to, is a quick and easy and cheap way to put the load on the power supply. Just make sure you provide a method for heat dissipation. Not sure if the fan will draw enough.
I use nylon cable ties to secure the resistor to the metal case of the power supply right against the ventilation slots. The metal acts as a heat sink, and the resistor gets plenty of cooling air flow in that location. It still gets quite hot but seems to be doing fine even after several years. - Jeff
wiring Welp,..I'm going to try using the extra fan this weekend, if it does not work, or if the fan someway starts heating up, then I'm going to switch to a resistor. Didn't like the light bulb idea, didn't want lights sticking out all over the place. Wish I could get this table done so I can finally start buggin everyone about trains,.giggity. THANKS TO EVERYONE WHO HAS HELPED ME OUT SO FAR!!
wiring Mr. Tray, thank you so much for the site links. They came in handy. But, I'm stuck and have a problem.(like usual) I noticed that I DO have a smaller orange +3.3 volt sense wire. All the sites say to tie it in with the brown wire, or connect it to the orange wire that it was paired with on the connector. Well,......I dont have a brown wire and I already cut off ALL the connectors. So,.. can I just hook my sense wire to 1 other 3.3 orange,. or do all orange wires have to be connected to it. I'm so close I can smell it,.. just a tad outta reach.:ru-err:
I'm sorry, but I don't recall doing anything with a sense wire. My power supply was a fairly old one, so perhaps it didn't have a sense wire. I would say you can probably connect it to any orange wire, but I don't know for sure. Have you tried the power supply without connecting the sense wire to anything? - Jeff
wiring Thank you very much. I will try that first and see what happens. When it's actually done I wanna put a pic on of it.
power supply wiring Ok,... so I hooked everything up. I followed all the instructions from all the sites. I also halted on hooking up the sense wire till I tested it first. Here's how it went. Everything is working a little too well. My 12v ran at 25.6v,... my 5v ran at 10.7v,.. and my 3.3v ran at 8v. I know the 5 and 3.3 aren't very necc. but hey, their there, Right? So,.. what could I have done wrong? Why are they testing so high? And how do I fix this? The only thing I can think of is taking off the resistors. :tb-confused:
It sounds like you measured the 12V between -12V and +12V, rather than common and +12V. Similarly, did you measure the +5 and +3.3 against the -5V, rather than common? To get the nominal voltages, everything needs to go against the common (black) wires.
pc power supply I have 6 posts. 3 common(black). I did 1 for each even though I know I didnt have to. And 3 red posts. 1 for my yellow 12v, 1 for my red 5v, and one for my orange 3.3v. Now I did hook up 2 10w/10ohm resistors. I was thinking of unhooking them to see iff the power drops, or anything else goes wrong. How can I post a pic of it so you might be able to get an idea maybe?
