This project is shared on PCBWay https://www.pcbway.com/project/shareproject/C64_ZaxxDual.html
While working on a project to replace the PLA in one of my Commodore64’s I came across the fact that the game cartridge ‘Super Zaxxon’ seemed to fail unless the PLA substitute was very good. After looking to buy a cartridge and finding out how rare they were I decided to build one based on the circuit from https://www.hackup.net/2018/10/super-zaxxon-replica/ . eslapion gave me the suggestion of putting BOTH Zaxxon and Super Zaxxon on one cartridge . This is the result , and it works very well!
This is my redrawn schematic.
To build the cartridge you will need a soldering iron and a pair of small side cutters. You will also need a way to program the ROM.
Start with the 10k resistor ( i always build by component height ).
And then the IC sockets , making sure to match the notch on the socket with the picture on the board. I tend to put the sockets in and solder one pin then hold the socket to the board and re-melt the solder so that the socket sits flush with the board and is held in place.
Solder all the pins. Then we fit the capacitors. I normally put them through the board and then bend the legs outward slightly so that they hold in place.
Solder them in and clip the legs off as close to the board as possible. Lastly fit the three pin header , again solder one pin first and melt the solder to line it upright.
You should now have this , ready to populate ( put the chips in ).
Remember to match the notch on the IC with the notch on the socket.
If you want more information or the binary files goto This forum.
I also have another project on PCBWay , an adapter to use a 512k rom as a PLA in a commodore64 the project that started it all off for me.
Thank you for L@@KING and hope you have fun!!
On a final note I would recommend at the very least the 1um gold fingers (ENIG) and the 30 degree bevel options for the PCB.