C64 PSU rebuild question

MIDIbox SID
1

I decided to rebuild my C64 PSU instead of building a whole new PSU, and I have two questions that I am hoping someone will know the answer to.

  1. Does anyone know a suitable transformer available through mouser or digikey that matches the ones in C64 brick PSU’s?

  2. Has anybody replaced the 3052P with a 7805? If so, other than the difference between pins, are there any other modifications that I need to make?

Thanks,

grizz

2

For a transformer I’m ordering a Hammond 266M18 tomorrow. It has dual 9V windings. It is available from Digi-Key and from Newark, maybe Mouser. Also, Canadian electronics reseller Electro-Sonic now has an American presence, check their web site at www.e-sonic.com - maybe their price is better.

I’ll be using one 9V winding directly for the AC, and I’ll be using a regulator on the other winding to give 5V. The regulator is LM323K, which works like a 7805, but bigger. Digi-key part # is 497-2976-5-ND.

This is not a cheap solution but if all goes according to plan it should provide years of trouble-free service.

I still need to buy a suitable heat sink and an enclosure.

3

I just re-read your original post. Just wondering: you say you want to rebuild instead of building a whole new PSU … but once you’ve replaced the transformer and the regulator, the only thing really left is the enclosure and just a few support parts. Why not simply start fresh?

4

I just re-read your original post. Just wondering: you say you want to rebuild instead of building a whole new PSU … but once you’ve replaced the transformer and the regulator, the only thing really left is the enclosure and just a few support parts. Why not simply start fresh?

I figured that replacing parts on the C64 power supply makes sense since everything I need is there… case, cords, etc. after replacing the caps and the blown fuse on the 9vac line it seems to work perfectly. I powered it under a load for about an hour, monitoring both the 5v and 9vac lines and all seems fine.

I still have a noise problem that I thought ditching the cheap switching PSU i’ve been using would fix.