ATT mike (home pin) and other techs
Either i am wrong or rotten dog have made a big boo boo on the bps018
I have edited the bps022 schematic so it resembles the bps018
on schematic BPS022 pins 9, 10 and 11 on J4 go to U7 which is a inverting Octal buffer / line driver ( which should have pull up resistors on these pins) which then drives Q17 to Q19.
When any of these 3 inputs are grounded (0 volts) the outputs on U7 go hi (+5 volts) which then turn on Q17 or Q18 of Q19.
But when you look at the schematic labelled BPS018 Q17 to Q19 (highlighted in green) are directly driven by pins 9 to 11. They have also added 3 pull down resistors (again surrounded by green) under the pcb.
So Q17 to Q19 are on when they are supposed to be off and off when they are supposed to be on. (which is wrong)
please tell me I am wrong.
