SCI Multitrak losing clock pulse
Posted: Thu Jul 23, 2009 5:01 pm
I'm about to jump out the first floor window with this Multitrak. Going cross-eyed looking at datasheets and schematics.
I'm trying to get the clock pulse to the CPU. On the clock divider chip (the 74HC74 chip) my clock pulse is present at the input (pin 11) but vanishes at the flip-flop output (pin 9). I substitute the divider chip with another and same deal. Voltage, resistors check out ok. I am using 74HC74AN chips. The previously installed chips were 74HC74N, should I go back to them?
I'm trying to get the clock pulse to the CPU. On the clock divider chip (the 74HC74 chip) my clock pulse is present at the input (pin 11) but vanishes at the flip-flop output (pin 9). I substitute the divider chip with another and same deal. Voltage, resistors check out ok. I am using 74HC74AN chips. The previously installed chips were 74HC74N, should I go back to them?