Modify VIC-20 for USB power supply?

[djc6]

I noticed in one of Adrian Black's videos, he uses a bench power supply to supply 5V @ 1.1A to his older VIC-20 with 2-prong power supply. In video he indicated the only thing that wouldn't work is 9VAC for the cassette motor:

https://www.youtube.com/watch?v=BGnNlVzUCZM&t=528s

I have a VIC-20 with missing 2- prong power supply - anyone ever replace the 2 prong connector on the computer with a USB connector, to power the board this way? I'm trying to find some alternative way to power board since I don't have the original power supply.

[JonBrawn]

I run my VIC-20CR from a 2A USB charger, but it has the DIN connector power plug. I doubt that connecting 5VDC to the 9VAC input pins would do anything useful. From the schematics I've got in front of me, you'd have to disconnect the voltage regulator's '5V output pin and then connect your USB 5V to the hole that came out from.

[freshlamb]

A lot of laptops used 9V line lumps. At some point I plan on going to my used junk store (Value Village) and getting a used one for my 2 prong Vic. The old 2 prong Vics line input was 9V AC and it separated everything inside. That power section, as I remembered used to get REALLY hot. Maybe it would be better to do something like Adrian Blacks power supply replacement for the 1541.

[mathop]

FWIW:
I have 2 VIC20's (PAL and NTSC variant), both with the 2-prong power socket.
I use a 9VDC 2.25A power supply with crocodile clips, with some improvised plastic bits to avoid shorts; that appears to work fine.
Previously I would power it with 8.9V from my bench supply, then it draws about 1.5A.
I think you need at least 8.9VDC to power it, the rectifier drops about 1.4V, and the regulator needs at least 7.5V.
Also the rectifier/regulator doesn't get particularly warm, I was worried about the heat at first. (Mind you I'm not doing much with these machines.)