C64 PSU Question

MIDIbox SID
1

Hi everyone

I’m really enjoying this project

Great forum with nice people

I have built

http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf

and am using 2 sid one core

I’m connecting the modules firstly to a safe power supply where im going to power it up and if there are any shorts it will tell me, I wanna do this to be safe with the circuit, and so I can Identify any problems before I use the C64 PSU

I’m using the newer SID chip the 8580 and using a C64 power supply that came with the newer C64.

I’m finding it difficult to identify all the PINs especially PIN 6 coming from the C64 PSU and into the socket and into the power switch on the left of the diagram.

I’m taking it that PIN 7 is 9VAC, PIN 2 is Ground, and PIN 5 is 5VDC

Here is a schematic of the C64 power supply

http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/c64extps.gif

This is probably a complete Newbie question but I just want to be sure

Thanks in Advance

PJ

2

Hi PJ,

as far as i know, all versions of the C64-psu had the same pinout.

So, pin 6 is located as shown in that picture.

It doesn’t matter, if you exchange pins 6 and 7, because the AC they deliver gets rectified afterwards.

You can see that in the pdf: those diodes marked “X1” are the same for both lines.

To identify pin 5, just use a multimeter.

3

Also, sometimes a C64 PSU has the 5V pin on the other side of ground. It is safe to connect both those pins together on the socket side (this is what I did on MB-6582 PCBs).