Hola, I followed step 4.4 in the HB assembly manual. I hold down STOP-SW while powering on the board, then the battery LED light for 1/3 s, but the power light does not go OFF. I have checked that the MODA signal and the RESET are present at the (...) (28 years ago, 11-Feb-97, to lugnet.robotics.handyboard)
there is no special "mode unlock," so you may have a bad 6811. -fred In your message you said: (...) (28 years ago, 11-Feb-97, to lugnet.robotics.handyboard)