Friday, January 1, 2010


For all of those who purchased an Obtronix board (not the kit) on ebay several years ago, there is a bug on this board. I can't say we all have the same board, but the board I have is missing a trace on D7 (74161) from pin 7 to pin 10. This bug was causing characters to repeat after a reset. I soldered a jumper wire across these pins, and the repeating chars stopped. This bug was found by Mike Willegal ( I verified these pins were not connected by using a multimeter.


  1. Thanks for the notes John - you got me interested so I dug out my Obtronix (kit) and verified that there was a trace between D7:7 and D7:10. The trace is clearly visible on the top side of the board and ohm-meter verifies continuity between the pads from the bottom side of the board. My Obtronix board is labeled Homebrew 2005 in the solder layer on the bottom side of the board (above the "Apple Computer 1" logo, which of course is on the top side).

  2. I checked the two bare Obtronix boards I bought on Ebay and sure enough one had the problems you've discribed. The other board was just fine. Also a system from a complete kit that I built doesn't have the problems either.