(photos courtesy of Ray Carlsen)Yesterday master C= technician Ray Carlsen demonstrated the CBM VIC-20 Diagnostic cartridge on a later VIC-20 board. He connected the special VIC-20 Diagnostic harness to the computer and ran the tests. The photos show some of the test screens. When a keyboard dongle was attached, the cartridge report that the keyboard was bad. With the dongle removed the keyboard was reported as being good. When a C64/128 Diagnostic harness was used with the VIC-20 Diagnostic cart, the tests would run to a certain point and then lock up the computer. In other words, that C64/128 harness was not meant to be used with the VIC-20 Diagnostic cart. Ray has information on the Diagnostic cart at http://personalpages.tds.net/~rcarlsen/cbm/misc/diagcart/vic20%20cart/ He has not yet posted a schematic of the VIC-20 Diagnostic harness nor its user port cartridge.
Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
Since I posted the link on Denial, I reverse engineered the VIC-20 dongles from the code. They do all work, including the keyboard one. As I also have the c64 ones, they are quite different. I'd be interested to see how mine differ from the schematics of the 'real' one that Ray has.
ReplyDeleteRob
We could not identify the keyboard dongle; it may have been a C64 keyboard dongle. The C128 keyboard dongle is definitely different (and still doesn't work right with the C128 Diagnostic cartridge). The rest of the VIC-20 Diagnostic harness (with its user port cartridge) works perfectly.
ReplyDeleteTruly,
Robert Bernardo
Rob, because you having a working VIC-20 keyboard dongle, can you send that information to Ray Carlsen?
ReplyDeleteTruly,
Robert Bernrdo
I tried the cartridge without connecting the harness (I have to do it) but at the first line "ROMCHECK" it gives me a code that is always different like "CE" or "DE" followed by "BAD" and then stops. I have tried to replace the three ROMs taken from a working VIC20 but I always have the same problem. I don't find this kind of error anywhere. Also in the red bar I do not get the working time, the clock is absent, there is a strange character
ReplyDeletecan you help me?Thank you!