CR30, CR31 and R110 make an OR gate. When either or both inputs are high then their output to the input of inverter U7A is high. All those parts make a Mickey Mouse NOR gate.
When you use Diodes and Resistors to make an OR gate or AND gate, what is this called?
Cause I need to find schematics on the Diodes and Resistors and get the truth tables for these
R110 to ground makes the inverter input low if the inputs to the diodes are also low then the output of inverter U7A is high.
Yes both diodes have LOW logic stages, but how does a LOW logic stage get passed the anode of the diode? doesn't it BLOCK the Low logic stage from getting in and to the U7 input?
U7A feeds a "box" called U12 but the schematic has no part number for U12.
4017 to a 4043
Why did you lift D31? Did you measure the voltage (with a shielded 'scope probe and cable) at its cathode and anode before lifting it?
When R110 makes the input of U7A low then should the output of U7A be high or low? Do you know?
To Isolate the board, to see if the short or problem is before or on that board, plus i can inject a HIGH STAGE to see if I was going to get the Comp fail light to TURN OFF
It turns on with you enable the flip flops and that BUSS line with everything connected to it
The Flip Flop that is connect to Q10 that turns on and off the Comp Fail light , should be at Zero volts , but i'm getting +14 volts
I have changed Q10, Diode, flip flop, U12, U7 , CR13 , nothing has worked , the +14 volts is still on the flip flops output for Q10 , it should be Zero volts on the output of the Flip flop going to Q10