I did my best to make this design safe but overall I am an amateur and hobbyist. I can't guarantee you won't hurt yourself during making this thing, so if you feel uncomfortable to work with electricity, please don't start playing with it.
As well, this is not laboratory power supply. I don't know the level of noise or any other parameters which is required for lab PSUs, so don't even think about this thing that way.
Bench top power supply built on top of an old TFX 250W power supply (you can probably by one on your local market for about $10-15)
The design is inspired by the "Back Horn Speaker V2.0 BL2 - Bluetooth, Active, Passive" by guppyk (https://www.thingiverse.com/thing:4668173)
BILL OF MATERIALS
Product | Amount | Link
Rocker switch | 5 | https://aliexpress.com/item/1000005699023.html
Dual USB charger | 1 | https://s.click.aliexpress.com/e/_AmzlmT
12V LED rocker switch | 1 | https://s.click.aliexpress.com/e/_ANc8qP
Step up buck converter | 1 | https://s.click.aliexpress.com/e/_9vhU95
Buck Converter CC CV 1.8-32V 5A Power Module | 1 | https://s.click.aliexpress.com/e/_Ac5D8P
0.56'' 0-100V 10A LED Digital Voltmeter Ammeter | 3 | https://s.click.aliexpress.com/e/_9vbHCJ
Fuses (5x20, 10A) | 4 | https://s.click.aliexpress.com/e/_AaPtEL
Fuse holders | 4 | https://s.click.aliexpress.com/e/_9jOzf9
Banana socket (red) | 4 | https://s.click.aliexpress.com/e/_AU55QT
Banana socket (black) | 4 | https://s.click.aliexpress.com/e/_AU55QT
2x 22 Ohm 10W resistors or 1x 8 Ohm 50W resistor with heatsink | 2(1) | https://s.click.aliexpress.com/e/_AVklGr https://s.click.aliexpress.com/e/_9gjnQx
IEC socket | 1 | https://s.click.aliexpress.com/e/_9xd9PH
LM2596 step down converter (optional, for fan speed voltage control) | 1 | https://aliexpress.com/item/4000064597454.html
Sunon 6010 12V fan | 1 | https://s.click.aliexpress.com/e/_A7tuKR
Insulated connectors | 1 set | https://s.click.aliexpress.com/e/_AnuYWR
Some of the above links are affiliate. If you feel uncomfortable with this try to search products on your own.
I will post assembly instructions soon. If you have any questions now, please post a comment or send me PM message.
Wiring scheme is included in files list (PDF) and on the preview images list.
Prepare yourself for a long print. I am printing quite fast (about 100-120mm/s) and I was printing outer walls for about 14h on 0.28 layer height (0.4 nozzle).