NEW CODE FOR C64 DIGANOSTIC CARTRIDGE: 588220* FOR THE C64 & SX-64

               latest updates and corrections 7-26-2018

     I am pleased to announce revised code for the C64 diagnostic cartridge to allow tests of the SX-64 computer. The original code in the 586220 cartridge was made for the C64 and it generated lots of errors when used on the SX. Parts of the code were rewritten so the same cart can now be used with the SX as well. The IC in the cart is a 2764 EPROM and so it can be erased and reprogrammed or a new EPROM programmed and fitted. 
     Of course a complete test of all the ports requires the "octopus" able, the same as used with earlier C64 and C128 diagnostic carts. A different keyboard dongle must be made for the SX which has a 25 pin D female recepticle on the underside of the computer. As with the C64 & 128 keyboard dongles, this one cross connects all the columms with the rows (0 to 0, 1 to 1, etc.), as shown in the diagram. I built mine so it doesn't need to use the existing keyboard cable but alternatively, one can be made to fit the other end of that cable so it can be tested, and would be easier to use as well.
     The internal 1541 in the SX must be disconnected (unplug P11 on the I/O board or P19 on the FDD board) so it doesn't corrupt the readings. Since there is no cassette port on the SX, that will show "open" and if there is no adapter plug on the keyboard connector, it will also show "open" or "bad". If any other than the original SX Kernal ROM is installed in the SX (such as JiffyDOS) the cart program will default to C64 diagnostics and the readings will show errors. 

586220 (c64) and 588220 (sx64) diagnostic plus.
Kernal detection and reassembly by worldofjani.com
Additional kernal checksums by Marty / RADWAR
SX-64 Tape Port check removal by KiWi / www.SX-64.de
Chip number detection for SX-64 or C64 by Ted Saari <theoisle@aol.com?>
Expanded window for paddle test by Sven Arke 

Ray