nil-x

I bought a new c-64 PSU - one of the nicer ones that are repairable. now the 5vdc is working and the sid is getting the 12v it needs. And you're right, it's not fried. It does however have an issue with voice 1 - it doesn't track the keyboard correctly, osc2 and 3 do - I assume it's the SID, I understand they can have bad voices though. Otherwise, it's working great! I'm gonna order a NOS SID chip now and then start on Step A, the minimal CS.

the 7812 is correct, It's probably the PSU. I plugged the +15vDC from my modular power supply and got 12v at the +v pin. (though I still didn't get any sound) The voltage stayed the same with and without the sid installed. I think the load is causing the commodore psu to 'sag' I need to check all the pinouts on the psu to make sure I'm getting the 5vdc mixed with the 9vac like the schem, I may just be getting the 9vac which would count for the sag when a load is present. Do you think the SID would be damaged from a 9.4v instead of 12v? I did have it on for a minute or so.

I built the midibox sid and I think the 6581 is bad. I have no way of testing the sid because the commodore I got, I hacked to get the parts for the power supply. For one, the 6581 gets kinda hot. I get no audio out. The +v pin is 12v (edit: actually it's 11.1v) when the sid is not installed and is 9.4v when it is installed. I do get 5v on the other pins when I run the interconnection test. More info about my setup. It is just the core and the sid module. I am not using a bankstick (do I need to do anything because of this?). The core and midi seem to work fine. I'm using the c64 power supply using the schematic for connecting 1 sid (non-optimized). Any thoughts? Am I right in thinking the sid is bad or is there something I'm missing.?