The positive supply connection to A22:U7 (LM339 quad comparator) is shown as ground in the circuit diagram. This is surely incorrect as the inputs of U6B and U6C are connected to TTL(+5V VCC) signals.
Surely this is not the designers intention The positive supply of A22:U7 should be +5V. Is there a manual change correcting this schematic error that I have missed? If A22:U7 positive supply is indeed ground, the circuit may still work but its reliability will be compromised by the relatively large currents flowing into A22:U7C&D input substrate diodes. Bruce _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
