Bulding an Easyflash cartridge

I bought an EasyFlash for my C64 some time ago and put Turrican on it. So happy was I with the near instant load times, I decided it was staying on it forever, and even went so far as to make a laser printed box and cartridge label for it:

IMG_20180117_171351.jpg

I was so pleased with the results and to see a nice new looking game box in my collection, I decided that I wanted more games like this. However I needed more Easyflash carts, and the cheapest I could find was £25 each on eBay. So I decided on a different approach, building my own.

The first step was finding the PCBs. This proved to be a tricky task but eventually I found a site with the designs on it for fabrication: DirtyPCBs. Ten boards from here cost about $25 with shipping, they’re coming from Hong Kong so will take a few weeks. Using the parts list below I sourced the remaining items from EBay and RS-Components. The total cost per cartridge works out around £10, not a bad saving, especially as I want to make multiple!

Parts List

  • 16 Pin DIP socket
  • 28 Pin DIP socket
  • 2x PLCC 32 sockets
  • 74HCT00
  • 74HCT02
  • 74HCT74
  • 74HCT174
  • 74HCT175
  • 2x AM29F040 Flash rams
  • Sony CXK58256P or other 62256 equivalent SRAM
  • 8x 0.1uF tantalum bead capacitors
  • 2x 10k resistor
  • 1x 1.5K resistor
  • 2x 8pin 4resistor isolated resistor arrays 100R
  • 3mm green LED
  • switch (small)
  • push button small

The way to solder components for these things is to start with the lowest profile  stuff and work up. And so the first thing is to solder a bridge link on the board between the two PLCC sockets. I created the wire links out of resistor leads as I have plenty of resistors and they’re cheap.

Next up the resistors, the 1.5K goes in the R2 slot and the other two 10Ks goes in the R1 & R3 slots:

IMG_20180209_214021.jpg

Then the capacitors, they’re all 0.1uF so it doesn’t matter where they go, just fill all the slots. Then the 3 smallest ICs, the 74HCT175, resistor arrays and the two DIP sockets:

 

Then finally the switches, LED and PLCC sockets. Before plugging it in to a C64 you have to take some measurements on the SRAM socket to test for short circuits. Resistance between pin 14 and 28 should read as OL (open line) when the switch is toward the reset button and approximately 9.5-10K when it’s not.

For sanity’s sake and to make use of my new toy, I examined the board solder with my stereo microscope. It’s a great tool as my eyesight is not what it was and can help you solder very small surface mount components. In this case I just want check for solder splashes and bad joints:

All looks good so finally the cartridge is written by plugging it in with the switch set toward the reset button (lets the C64 boot normally) and using EasyProg to write CRT files to it.

There’s already some EasyFlash images over at CSDB along with all the other tools you might need. Including EasySplit, a tool to split the large CRT files into pieces that will fit onto a 1541 floppy disk.

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