original c64 psu pumping 12v

Testing/Troubleshooting
1

hey, so i rebuilt my sid synth from scratch and i’m using the original c64 psu (6581 sid).   the diagram (http://www.ucapps.de/mbhp/mbhp_sid_c64_psu.pdf) says that pin 1 of AC1 should be 9VAC but i’m getting 12V AC.  could this be why it isn’t working?  also, is there any way to test  the voltages coming out of AC2 and pin 2 of AC1?  right now they read 7VDC (zero VAC), but i know that’s wrong.  i am getting 5VDC going to the diode, however, so that’s working at least.  the 470uf cap i’m using is from the original c64 circuit so it’s 25V instead of 50V, but that shouldn’t matter, right?

thanks

james

2

Everything right (the cap and stuff) but only one thing: *Every* PSU has much more voltage if there is no current going out. So the 12V instead of 9V is OK. Give it a little current (like at least 50 mA) and you will see it dropping. Anyhow that should be no problem, because the 78xx is getting the voltage down to the needed level.

Greetz!