Jim Brain writes: > > On 5/4/2022 10:50 AM, Uffe Jakobsen wrote: >> >> >> Isn't the output of the the reset "timer-circuit" driven by 7406 and a >> pull-up on all board revisions ? >> >> > > Nope: > .... > > Response (bottom third of the page) from skoe: > > " > We found out that ASSY 326298 REV A actually has an unusual reset circuit. It > is not implemented like it is shown in the schematic #326106. Instead of > using an open collector output and a pull-up resistor, they left out the > pull-up R36 and connected the reset line directly to the push-pull output of > the NE556. This is surely an obvious design flaw. They fixed it in the next > revision. > > Bad news: The NE556 can drive +/- 200 mA (!!!) according to its datasheet. > This is too much to be overridden by the EasyFlash logic. I think only a > mechanical reset button can do this (or very strong logic outputs)." > Oh I see - I never checked if the 326298 REV A board actually matched the schematic... Regards UffeReceived on 2022-05-04 22:00:02
Archive generated by hypermail 2.3.0.