IBM PCjr ATX Power Adapter

IBM PCjr ATX Power Adapter, US Shipping

ATX2PCjr Kit $15 + US shipping
ATX2PCjr Kit Assembly $5/ea
ATX2PCjr Kit International(outside the US) Shipping Extra $7*

I've been told this doesn't work with 24pin ATX PicoPSU versions because they stick up too high on the PCB. I currently have no plans to change the board design to try and work around this. There isn't a lot of vertical space left to move the connector lower. I would just recommend making sure you only get a 20pin PicoPSU.

*After getting estimates to three different countries it seems like international shipping always comes out to $14 via USPS. So I've added an option to include an extra $7 for international shipping. If that ends up not being enough or was wrong for your destination then I'll email you to let you know and offer a full refund if the shipping is too much.

If these are sold out please email me at so I can get an idea of how many of these I need to order for the next batch. I can also let you know when the new ones come in.


Open Source

Yes, the design files are all up on Github. I don't lock down my projects so that their continued existence is reliant on my input. The EDA and CAD files needed to make these from scratch are all in there.


Q: What is a PicoPSU and/or where can I get one?


Q: Which PicoPSU/What Power/How Many Watts ... should I get?

A: The exact one I am using is available here: The only thing you need to worry about when choosing a PicoPSU is the ATX power connector. It needs to be a 20 pin model. The original PSU in the PCjr was only 33W and as far as I know, all PicoPSU's are rated for more than that. You will also need a 12V power supply able to put out at least 3A, more is fine. At the link you can add a suitable PSU if you want to go the high quality route. Adrian Black tried out using a cheaper ebay option and it seems to be working fine for him. I haven't tested them myself.

Q: I have a 3D Printer, can I order this without the printed parts for a lower cost?

A: The cost of the printed resources come out to about $0.25. I'm not even including it in my pricing model. So you're getting them for free anyway.

Q: With this I can power all my side cars without a power side car right?

A: I am strongly recommending against that. The PCjr system board wasn't design to handle high power delivery through the expansion connector. I don't know what the consequences of doing so would be.

What you get

Assembled Version

  • The power board ready to plug in
  • Two 3D printed rear panels for ATX or PicoPSU use
  • A cabled switch to be installed in a 3D printed panel with mounting screw

Kit Version

  • The power board PCB
  • Molex 20-pos Mini-Fit jr connector (ATX Power)
  • Amp 4-pos connector (floppy power)
  • 3-pos 100mil pitch male header (fan connector)
  • 2-pos 100mil pitch male header (switch connector)
  • Two 3D printed rear panels for ATX or PicoPSU use
  • A panel mount switch (power control)
  • 2-pos 100mil pitch female header (switch connector)
  • 2 wires (power switch)
  • Shrink tube (power switch)
  • Screw (power switch)