Power Supply Question

teckkev

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I have a PC style power supply. It has:

3 red (+5)
3 Black (Ground)
1 Yellow (-5)
1 Blue (+12)

Run N Gun was working on it but edge was getting burnt (+5)

I'm wiring cab to my setup. I tied the reds together and getting -0,08 reading. Is the +5 wires on their own source and can't be tied together? I'm puzzled to the reading when the Run N Gun PCB worked fine. The +5 adjustment does not do sqaut on the reading.

Thanks,
Kevin
 
In the "XT" computer style power supplies with 9 pin Molex DC output connector, the three reds all go to the same +5 volt trace on the power supply's circuit board. Same with the black common (ground) wires----they all go to the ground trace.
 
That is what I assumed.. ideas to the reading I am getting? Only thing I remotely can think of cab/power supply not properly grounded (but why would the pcb work). The odd reading is same for -5 and 12. I even get a low reading from ground! Thanks for the XT remark.. I knew it wasn't ATX and doubt it was AT :)

Thanks,
Kevin

Meter is good, I even went to another cab and did a reading with normal results.
 
If you're just measuring the +5 with nothing connected, the supply might not be turned on. There are many web pages about using an ATX supply as a test bench supply. Here's one: http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

You may need to connect pin 14 (power-on) to ground to turn on the supply. Some but not all supplies also require an actual load to turn on. Usually, a 10 Ohm power resistor is connected from +5 to ground as a dummy load.
 
It's not ATX. I know power is on :) I don't have a load. I want to do a reading before I hook a PCB to it.. I guess I could use a cheap jamma pcb to give it a load.

Kevin


If you're just measuring the +5 with nothing connected, the supply might not be turned on. There are many web pages about using an ATX supply as a test bench supply. Here's one: http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

You may need to connect pin 14 (power-on) to ground to turn on the supply. Some but not all supplies also require an actual load to turn on. Usually, a 10 Ohm power resistor is connected from +5 to ground as a dummy load.
 
Yeah, just throw a 10-Ohm resistor in there. 3W or better should be fine. Or yeah, a cheap jamma board.
 
Do the ATX PC power supplies need a load on them? I want to test to make sure this will work. I am trying to use one to put into a cab that is running a PC monitor and a 60-in-1 board.
 
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