CHANGE LOG

2021-03-16

• many people started notifying me, that rocker switches listed on BOM are too small and it's true. I mistakenly added link to 10x15 version. The correct size for switches is 15x21. I corrected the link in BOM already. Sorry guys!

2021-01-10

• added photo of used TFX power supply: the exact model is Fortron FSP250-60SBV
• updated info about brass inserts in BOM (it is designed for M3 X D4.6 X L5.7)

2021-01-09

• STEP file added to allow you modify the project easily
• Assembly guide added (please find attached pdf in files list)
• added stl files for top and bottom lid - for those who don't want to cut them out from plywood
• added pdf template for cutting the top and bottom lids
• added melt-in brass inerts to the BOM

Disclaimer

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.

Introduction

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 (2 pin, 15x21)	5	https://s.click.aliexpress.com/e/_Aru962
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/_DkuwFWJ
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/_9gjnQx
IEC socket	1	https://s.click.aliexpress.com/e/_DBjm3Rt
LM2596 step down converter (optional, for fan speed voltage control)	1	https://s.click.aliexpress.com/e/_DkHltWB
Sunon 6010 12V fan	1	https://s.click.aliexpress.com/e/_A7tuKR
Insulated connectors	1 set	https://s.click.aliexpress.com/e/_AnuYWR
Brass Hot Insert Nuts M3 X D4.6 X L5.7	12	https://s.click.aliexpress.com/e/_A1hMur

Some of the above links are affiliate. If you feel uncomfortable with this try to search products on your own.

Assembly

Please look at the Thing Files list for full guide

Wiring

Wiring scheme is included in files list (PDF) and on the preview images list.

Printing

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).