Task: Build a 2-in-1 Dead and Diagnostic Test Cartridge for Diagnosing Non-Working Commodore 64s
Needed: 2-in-1 circuit board, two EEPROM chips, an EEPROM programmer, two 100 nF capacitors, soldering iron, cartridge case and screw(s)
Time: 1-2 hours
Disclosure: Note that as an eBay Partner Network Affiliate, I may earn from qualifying purchases.
Introduction
I have previously posted about purchasing and using the Dead Test and the Diagnostic Test to diagnose and troubleshoot non-working Commodore 64s. At the end of those posts, you can see the 2-in-1 cartridge I purchased that features the Dead Test on one end of the cartridge and the Diagnostic Test on the other. This makes it very convenient for testing and avoids the need for multiple cartridges or setting jumpers on a single one. I have been very happy with my 2-in-1 and decided to learn the process of making my own.
What makes this project possible is the awesome 2-in-1 circuit board designed by C64iSTANBUL and provided as a shared project on PCBWay for easy ordering.
Instructions
Step 1 is to purchase the circuit boards from PCBWay. Create an account if you don’t have one and navigate to the shared project. Once there simply add it to your cart. The default settings for the order should be fine. I ordered 10 boards at a cost of $1 each with an additional $20 for shipping by DHL. This was about $3 per board and took about two weeks to arrive from China. There are cheaper, but perhaps less reliable, shipping options you can try to bring to cost down.
Step 2 is to order the EEPROMs. There are several models that will work including 27c64, 27c128, 27c256, and 27c512. I ordered 10 W27C512 EEPROMs from eBay for less than $20 or about $2 each. You need two of these for each 2-in-1.
Step 3 is to burn the software ROM files onto the EEPROMs using a programmer. Mine is an XGecu Pro TL866 II Universal Programmer. Simply load the ROM files into the programmer software, insert the EEPROM into the programmer, and choose Program(P) from the Device(D) menu. The programmer will erase the EEPROM, burn the ROM file, and then verify the image. This takes just a minute. It is important to note that you need to use the 64K ROM files provided at the end of the PCBWay shared project. The EEPROM won’t work correctly if you use a smaller ROM file (I tried!). Burn one for Dead Test and second one for the Diagnostic Test.
Step 4 is to solder the EEPROMs to the circuit board with notch matching the silkscreen image on the circuit board. See mine above as a reference.
Step 5 is solder two 100nF capacitors to the board where indicated. Any orientation is fine. I got my capacitors in a kit from Amazon for $13.
Step 6 is to test the board by inserting each end into the cartridge slot and booting the Commodore 64. Remember that the Dead Test will need about 5-6 seconds to start up.
Step 7 is to 3D print or order a cartridge case. There are several designs freely available online for download and printing. Here is a top shell from Thingverse that goes with this one. You can download the STL files and either print these yourself or send them to a service like PCBWay that will do it. I ended up designing and printing my own case so I could retain the rights to sell these when finished. I plan to put the STL files on my Etsy shop at some point.
Step 8 is to assemble the final product!
Comments
This was a fun project, and I love these cartridges. I ended up making eight in the end. One was a failure due to bad chip. Another I installed sockets on for future development and testing. I plan to sell the extras as a future VCF event or online. I am not sure I would do this again as it was a bit of work!
I am selling my extras on Etsy for $30.
