ATX Bench PSU

This is a cross-breed of robertguy and flash24's bench PSUs. The body is designed to replace robertguy's one-piece unit to make wiring a little easier for those of us equipped with sausage fingers. But I've also added the independent fusing and per-output meters of flash24's design.

See:

https://www.thingiverse.com/thing:2450705

and

https://www.thingiverse.com/thing:3084935

for details of their designs.
 

I intended to make the front panel attach with glue. I haven't done this yet, so mine's just held by friction at the moment. However, I don't know how well that solution will last, so I'm not gonna recommend you to do it!

For the USB section, I used a PCB mount USB socket with a separate 5 Volt feed from the ATX unit. The clip is there to hold this snugly in the front panel without any other fixings.

You will need to print out robertguy's rear case, and I trust you will take the time to "like" his project when you download. Don't forget to pop along and "like" Flash24's design too!

I am planning to add a step-up module to allow me to go up to 24 Volts on the DPS 5005 outputs, and I'm awaiting delivery of this part. If it works, you'll read about it here (See update below).

I haven't included any major wiring details as there are numerous videos and instructables out there. If you can't work it out, you probably shouldn't be messing around inside an ATX PSU, as it can be a lethally dangerous place!

So the only wiring I'm going to mention directly is the "ballast" or "load" resistor I have hard-wired between 5v and ground. I happened to have an aluminium-bodied 10 Ohm 10 Watt resistor in my parts cache. I placed this inside the original ATX case, on the rear outlet grille. This allows the grille to act as a partial heatsink, whilst the air exhausting from the case will also add cooling to the resistor. As my PSU is a cheapo, the fan is always on so the cooling is constant.

Finally, HUGE thanks to robertguy and flash24 for their designs which form such a major part of my version. So, thanks Rob, and merci Flash24!

Small update:

I finally got my XL6019 boost converter module, and set about fitting it. Setting it at about 26 Volts, it appears to give the full 24 Volts from the DPS 5005. But - and I'm hoping the electronics whizzes amongst you can tell me why - the indicated output current on the 5005 is reading incorrectly.

For example, I connected a small 12 Volt TFT video screen that draws about 900 Milliamps, according to my multimeter (and the 5005, before I added the booster). But now the 5005 assures me that it's drawing 274 mA,whilst my multimeter still sees 900mA .

Further update:

I've noticed that the incorrect current reading on the 5005, which I mentioned in my last update, appears to be limited to this one particular load. But, in all other respects, it's working fine.

The mystery deepens. Where's Big Clive when you need him?!!

Print Settings

Printer Brand:

Creality

Printer: 

Ender 3

Rafts:

No

Supports: 

Yes

Resolution:

0.2

Infill: 

20%

Filament: ED-A PLA Yellow & Black

Notes:

To get the body to fit on my Ender 3, I had to modify the print bed dimensions in Cura so that it didn't "think" the design was too big for the bed. It fits ...just!

I was also having a lot of trouble with under-extrusion on my front panel. Changing the nozzle and clearing out the hot end made no difference. I usually print at 200 degrees, but I solved my issues by printing it at 216 degrees to get correct extrusion. I can't make my mind up whether that's down to Cura 3.5.0 teething troubles, my cheap filament, or simply the decrease in ambient temperatures as we progress into Autumn!

Category: Electronics