Mike's PCjr Page

I'm surprised this hasn't been mentioned yet, but a dedicated homebrew hacker built an ATX-to-PCjr adapter and is selling them for very cheap. They seem like a great way to get a PCjr up and running if you can't find a spare power brick. Final video here: https://youtu.be/AvoJXL1EUj8

The kit is available either assembled or unassembled. It also comes with a 3d-printed part and replacement power switch that does a good job of approximating the original.

It's actually not a bad hack. All passive components, so it would be pretty hard to mess that up. And of course the power output is going to be much higher than the original power supply.

I'm already using an external ATX power supply to power an external hard drive. This is tempting.

This is probably a dumb question, but I will ask it anyway.. that is usually how I learn.

How would the voltages be tied into the the other level upgrades, like the second floppy drive and even the third level hard drive? Simply by tracing the voltages and paralleling it all together? How would the pick wire come into play?

The Mouser PT-65-B switching power supply has +5V 5.5A, 12V 2.5A, -12V 0.5A.. would this have enough power to handle the requirements of the above mentioned ?

The 'pick' wire power comes thru the mother board side connector and the from the addon side car of thr Racore unit, it tells the upstairs pwr supply to turn on when the lower lever pwr supply iis turned on..

But I think you would want to get rid of the the second and third tier pwr supplies also, so I would opt to use the mouser PT supply.

I have not finished mine yet, waiting on my new 3 floppy controller breakout board.

as far as the other cables, yes you would need to get some 'Y' cables and make your hookups for the second drive and even the hard drive,

You would also need to make the pwr cable, 'colored ribbon' that plugs in the Racore side unitm 6 pin I think, so it would be a bit of work and planning.

Shelbys nice little Pico board is great for single tier Jrs, but the double and triple, in my opinion has the room to opt for the Mouser PT supply...

Chuckphd53 wrote:The 'pick' wire power comes thru the mother board side connector and the from the addon side car of the Racore unit, it tells the upstairs pwr supply to turn on when the lower lever pwr supply iis turned on..

I'm sure it could be figured out .

When you install the 3rd level hard drive, you end up switching power supplies.. the former floppy drive second level becomes the hard drive third level and vice versa so the DB9 power connection ends up in the middle. The rainbow power connector (now at the top level) that use to plug into the side car plugs into the "new" middle section power supply and that power supply has a rainbow connector that then goes to the side car.

Good info chuck, pictures as you go may help document this exercise, and do share with us...