ATX retro power supply rework

Thread Starter

Poppa D

Joined Aug 30, 2020
13
Couple years ago reworked ATX for voltage supply

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Ground: 3 wires (black)
12V: 3 wires (yellow)
5V: 3 wires (red) + 1 wire (pink)
3.3V: 2 wires (orange) + 1 wire (brown)
-12V: 1 wire (blue)
-5V: 1wire (white)
Rocker switch with light: gray, green, and black wires
1) My logic was if only 3 wires are feed I only need 3 wires for ground should it be more than 3 ground wires?
Wires NOT connected
Ground: 6ea 18g and 2ea 22g wires (black)
12V: 2ea 22g wires (yellow)
5V: 3ea 18g wires (red) and 1ea 18g wire (purple)
3.3V: 1ea 18g wires (orange)

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All voltages check out and have been using as is. Have overloaded a couple of times and unit shuts down but comes right back when switched off and on The main problem is ALL circuits, (including light on switch) cycle or pulse at a rate that is easy to see.
2) Suggestions on how to stop the pulsing/cycling of circuits.
3) Green wire has “PSON” written on pcb what does this mean?
4) What is 5V purple wire used for?
5) Is there any significance to the different gauge wires above?
Extent of testing equipment is Craftsman digital multimeter, so keep in mind when asking for any additional info. Thanks for taking a look and could use any help or suggestions!
 

Dodgydave

Joined Jun 22, 2012
9,666
The Green wire is to power the PSU up , you short it to Black, the Purple wire is 5V standby always there.

If you say you have overloaded it a few times chances are you could have blown an output diode and it's cycling due to over-current .
Ideally ALL wires of same colour should be connected together or use a single strand of thicker wire for the output sockets.
 
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Thread Starter

Poppa D

Joined Aug 30, 2020
13
Dodgydave, the cycling was present from beginning before connecting any loads to unit, should the Purple wire be connected to a Ground wire? Rocker switch wired Ground is Black, Power is Green and Accessories is Gray is this correct arrangement? Would led light have anything to do with cycling? What's best way to connect 11 ground wires to single large wire and what gauge wire should I use for single wire? According to label max current would be 27amps
 
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Dodgydave

Joined Jun 22, 2012
9,666
When I modify Atx psus, I connect the Green to Black, use the purple as the led feed with a series resistor, connect All Blacks together, All Reds together and All Yellows together , or remove all the reds,yellows ,blacks and use 1.5mm or 2.5mm cable as it's easier, you also need a 5ohms 10W resistor across the Red 5V supply to keep it going.
The switch I wire on the mains side.
 
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