Solve Multiplexing Conundrum with LS153 Circuit

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The discussion revolves around troubleshooting an LS153 circuit that is not producing outputs despite receiving the correct inputs. The user notes that only two of the four inputs are being sampled, which explains the lack of change in the F1 output. However, the F2 output remains inactive, raising concerns about the circuit's overall functionality in SIMETRIX. Suggestions include connecting an LED to the output for better visibility and creating an RS flip-flop with NAND gates to probe the outputs. A timing diagram is also recommended to diagnose potential frequency issues between inputs.
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Stuck with simple LS153 multiplexer circuit
Hello,

I am hoping that you could help me understand why my simple circuit is not generating any outputs.
I used LS153 to design a circuit giving two outputs (4 to 1 conversion) on SIMETRIX.
The circuit when 'run' gets the required inputs (as I see them as a square waveform graphs) but the device is not generating outputs.
Would you be able to spare a moment to offer some clues as to what might be missing?
The inputs generated are as per the below table:

Outputs F1 and F2 will be true for AB and C states as listed:

A
B
C
F1
F2
0​
0​
0​
1
0​
0​
0​
1​
0​
1
0​
1​
0​
0​
1
0​
1​
1​
0​
0​
1​
0​
0​
0​
1
1​
0​
1​
0​
0​
1​
1​
0​
0​
0​
1​
1​
1​
1
1

Thank you all for any clues,

circuit.png
 

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Address bit A is always the complement of address bit B. So only 2 of the 4 inputs are being sampled, namely states '01' = 1, and '10' = 2. Inputs '00' = 0 and '11' = 3 are never selected.

That explains why F1 output does not change.

But it does not explain why the changing state of Not(C) does not appear on F2.
 
Thank you Baluncore, I narrowed the range of inputs just to get some response from the device on SIMETRIX.
I also created various 'single set of inputs' scenarios, and all did not produce any outputs.
What concerns me here is that the SIMETRIX does not even allow me to put a 'digital probe' on the output lines: I can probe any input lines but cannot probe output lines; it seems that the device is inactive but with all the various configurations of inputs, it remains inactive...there has to be a way to resurrect it...I hope
 
Either look for an LED indicator to connect to the output,
or, maybe it needs something to think about.

Make an RS flip-flop from two cross-connected 74LS00 NAND gates.
The outputs of your Mux go to the RS inputs.
You can then probe the Mux outputs.
 
If V1 and V2 are the same frequency there could be a problem. Try sketching a timing diagram. (yeah, using pencil and paper)
 
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