How to test power up a C64?

[twistedpneumatic]

I got a C64 with no PSU, and have 2 questions?

1: is feeding only the 5V rail enough to get it to power on(I expect no SID to work though?)
2: What is the best (cheap?) solution to getting a PSU for it?

 

[iz8dwf]

I got a C64 with no PSU, and have 2 questions?

1: is feeding only the 5V rail enough to get it to power on(I expect no SID to work though?)

No, on a breadbin (with the older bigger PCBs) the +5V supply for the VIC-II (and the SID) is obtained by rectification and regulation (with a 7805) of the 9V AC supply, I don't remember what happens inside a C64C (with the newer shorter PCBs), but might be similar.

2: What is the best (cheap?) solution to getting a PSU for it?

Make your own PSU.

Frank IZ8DWF

 

[Dwight Elvey]

The schematic at:

https://www.retro-kit.co.uk/user/custom/Commodore/C64/manuals/C64C_Service_Manual.pdf

shows +5v and +12V. The +12V uses a voltage doubler from the 9VAC to feed the +12V regulator. It states the +12v is used for the VIC and SID chips. I think you would want both +12v and +5V to power it. With not video, what would you be looking at?
Dwight