Commodore VIC-20: adding DC power input to an AC-only model
6DISCLAIMER!
Anything you do to your precious VIC is on you! If you're not confident soldering ... or sodering as the Americans call it for some reason ;) ... making physical modifications, etc. then don't let your VIC be your practice-run.
Remember ... it's better to measure twice and drill once rather than measure once and drill twice. Particularly in this case as if you position the 2.1mm socket incorrectly you may run into problems with the case (requiring filing) or the joystick/AC socket on the side panel.
Having said that ... maybe this is of interest to someone.
If you've picked up an early model VIC (two-prong 9VAC input) with no power supply it can be a bit tricky to get it powered. You can now 3D print replacement plugs and then connect them to a 9V power supply, either AC or DC, so this is definitely an option ...
Check out EMD69's video where he shows his 3D printed version - in Italian but he shows very clearly how to put it together:
https://youtu.be/pkmAbx2YLSU
But ... if you're using a DC plug-pack ... why waste power & generate heat by going via the bridge rectifier?
So my idea (well, not *my* idea as I'm sure it's an old one ... I was inspired by GadgetUK164) was to simply bypass the rectifier and go straight into the regulator, which I always replace with a modern version ("PSU5 No Noise" from EzSBC.com).
The drawback is that you will no longer have 9V on the User Port (really needed?) or Datasette port (required to drive the Datasette motor). So if you want to use the Datasette then you'll still need to go via the AC socket & bridge rectifier. However if you don't, then you can connect the DC supply directly and run your VIC quite a bit cooler.
You also need to ensure that you always use a correctly polarised DC power supply - I wire mine for centre-positive.
An earlier video I did showing a slightly different (newer) motherboard is here:
https://youtu.be/zg0w4Nnov3Q