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Logic Outputs Problem in 7493 IC

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_q12x_

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Hello from Romania.
I have all the counting ccts, for every number. This is counting to 16 and its the last one this 7493 can count.
I encounter a new and very weird problem. All the [Q] (QA,QB,QC,QD) outputs of the 7493 are not so good at outputting. At least to my components I tested so far.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

I simulated more possibilities and all failed. I thought maybe the simulator is not that good. But when I tried the BJT in reality, it still didnt work. I really want to believe it will work with opamps in reality, but if it will not work, it means the simulator is right.
I didnt try with mosfets in the simulator yet, they were just prepared there. I didnt test them in cct.
THe problem is the (-) that 'comes out' after these buffering devices. When they are on (-) on their output.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

I actually solved the problem using a tri-state buffer. They are the only component that are solving this issue.
Ive also get 10 pcs from aliespress. I start to value them now, when I actually need them. But they will arrive after 2 or so months from now.
- I want to find a solution (IF POSSIBLE) without them, or at least until they arrive.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

This cct I already make and it is working fine (in the simulator) is to output a decimal number for all the 16 binary counts.
Pretty much when is 0100 it will lit the 4th LED. When is 1000 the 8th LED and so on, from 1 to 16 (including 0).
You can see in the screenshot already.
I work on this cct and numerous problems for .... about 10 or more days. Very hard to do it alone !!! But I did it. so far.

I even have an easier output method than this very complicated cct I already built.
- Simply to display in binary. Like these 4 LogicProbe from Proteus simulator that I am always take for granted.
So we can do these first !
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

To make a simple binary counter [LED display], I will still need some sort of buffer, like the ones I specified already.
I wait for your response. This is a very complicated cct and a big problem for me.
Thank you and hope I will get some interesting answers! (mister @marconi , my Logical friend?haha)
And also Happy New Year 2023 to everyone that are reading my posts !
 
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I modified your picture and interpret it my way.
Its an interesting idea... IF those mosfets will work as I planned in my #22.
Currently I have problems interfacing 1 single wire with 1 single led. Nothing worked so far (in reality). Only in the blody simulator.
Thats the problem....
Your idea will be 'plan B' if the 4 wires will not be enough and get errors on all those 16 # LEDs.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

In the meantime I solved in the simulator the 555 delay problem... I have to try it in reality. Hope it works. Cross your balls for me.
 
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So, check this out
I tested some more in reality and nothing worked.
What it did worked, my 555 super dupper cct, but directly on the pins of the 7493-not on the diodes and when the counting was over the pin I connected. So if it was counting to 8, my 555 was getting an impulse and its led on pin 3 was lit for the duration (delay) I make it to work.
So after some more failures, I decided to get rid of all those damn diodes because whatever I was doing I couldnt get any signal from them. This is it.
Instead, I BELIEVE, I did it the proper way now. I connected 4 leds directly to the 4Q's of the 7493 to gnd. I know it should be inverse, from + to Qpin, and I did it like that, but the leds were litting inversed. So I had to put them to gnd. Sourcing through the 7493 pin instead of sinking.
The good news is that now I have those 4 leds litting in binary - perfectly !
But I do not have that 4 input AND gate that I made from all those 4 diodes. You understand what I was doing now?
And thats not the only problem. I will need... probably 2 or 3 AND gates with 4 inputs, 1 here in the binary logic, and others in the display # LEDs. Aaaah.... When you dont have what you need.... hard stuff. I really thought I will pull it out with the diodes. Im so dissapointed....
 
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I happen to have only 1 one:
CDB430E Romania 1979 IPRS Baneasa equivalent to SN7430N 8-Input Positive NAND Gates
And that will pe good enough for the logic side.
But for the others.... thats why I got into great length, doing it with diodes.
I will built what I can, and leave what I can not make as a hole and put a label there "complicated".
But I will be able to make it work to a point. We'll see.
Im happy I find this 8 input NAND gate. I will have to transform it into a AND to do the proper job and every other pins will have to be linked to +5V (High).
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

I also have:
CDB410E x2 Romania 1980 IPRS Baneasa equivalent to SN7410N Triple 3-Input Positive NAND Gates
They may be handy.... Also I will have to transform them into AND gates as well.
We will see.
I also have
CD4081BE x20 AND gates
But until I will commit to the display module, I have to finish this logic side with 8 input NAND gate/transformed into an AND.
 
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Earlier on, in your frequency counter post, we covered the unsuitability of diode resistor logic for AND or OR when used to detect a counter state and generate a very fast rise/fall and short duration reset pulse to RO1 and RO2 of the 7493. Because of the capacitance between anode and cathode of the diodes the circuit is too slow to produce one short clean reset pulse. Do you remember now? We had to use a semiconductor AND/NAND ic from the 74 or 40 series.
 
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I managed to make this thing work in reality !
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

The (right) 4 logic probes here in the image are LEDs in reality, counting in binary.
This setup here is the same as the diodes one (but way more complicated)
The only problem is that I dont have any other 7430. This was the only one. And is most probably a slow TTL version, very old and made by romanians somewhere in 80's. The good news is that everything is working. Well, until the end of these 4 lines.
I just measured all the Buss lines and all the outputs and inputs and I pretty much get the same result as with the diode version.
VERY STRAAAAAAAAAAAAAAAAANGE!!!!!!!!!!!!
The only difference now, is that I can use those 4 leds counting in binary on the buss line.
But everything is UNDETECTABLE on those 4 bus lines !!! yet, it is working.
AGAIN> VERY STRAAAAAAAAAAAAAAAAANGE !!!!!!!!!!!!
Why I cant measure them? I still get a very WEAK signal, close to gnd.
Maybe I dont know how to measure this thing? How in the hell are you measure such thing?
AGAIN> VERY STRAAAAAAAAAAAAAAAAANGE !!!!!!!!!!!! WOW.
 
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Indeed, and thank you that you watched my movie.
I just revert back to the diodes instead of the 8 input NAND and it is working....but for certain counts. Up to count to 8 everything works. But AFTER 8, is giving me errors. So the diodes not good in the logic side. I put back the 8 input NAND and tested every count. And I get this result:
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

Which is great news. Also the binary counting leds are doing their jobs fine, and also for the moment that single #1 module display also did it's job for everything so far.
I was thinking to replace this 4xAND diode gate with a 4input DTL NAND and a NOT also DTL.... But I will see.... What do you think? Should I ?
Next...probably I will have to make all the display #'s and see what 's*it' I will get from there.
This long tutankamon:
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC

This is how is looking now in reality and is also working in the simulator as well with minor changes (R9) and some errors, but is working.
As you can see, no transistors on the BUS. Directly from the 7493 !!! Which Im not really a fan, but, it works.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC
 
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I will check your posts but today and tomorrow I am visiting my elderly parents so I have less time to contribute(?) to your project.

I do not think you will be satisfied unless you test your Dtl logic gates first. You may need the source and sink circuit I sent you a diagram to drive 16 of them.
 
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Im on the wave !
I managed to make the analogue version of a NAND Gate +a NOT Gate !
Tested from 2 to 16, all working as with the real chips.
Excellent !
Check the picture in the bottom of it.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC
 
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Im starting to make the (card)boards for the 'display' counter (0-15).
Very retro looking and feeling.
A lot of work. I only finished #1 module and tested on my breadboard and working and I have a GO for the rest.
Hope you like it.
[ElectriciansForums.net] Logic Outputs Problem in 7493 IC
 
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Yes, I had a (wiring) problem on #5 and I figure it out. All messed up. Thank god it wasnt a logic problem. And after I seen that #5 is working, I get courage and filled the full length of the breadboard , to #8 and all worked just fine. I didnt make it to 16 since I dont have that many CLEAN diodes (legs). So I get another courage, round 2, and Im starting and HOPING that these cardboard ccts will do their job. I plan to make it until 8, like I did it on breadboard, and then put that in front and after it, on the breadboard to make it to 16 and this way make a FULL count of all 16 of them. Im also making a movie about it... from pieces filmed in time, as I progress.
Thanks for the interest. It looks nice, right? Hehe. But is a ton of work. Hope I will make it today... Mmmm
 
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marconi said:
the decoder box on page 2 does not show any detail but you have worked out what is involved.
Click to expand...
I dont understand what you mean by that... You mean that I figured out how to connect these 4inputs to get my 16 modes ?
I actually searched and didnt find a BCD for 4 bits(binary) to output 16 modes (decimal). I didnt searched well enough I guess, because here you are with it. Very good that you show it to me !
Are they even bigger that this? with 32 outputs maybe? or 64? That will be cool to see ! Haha.
 
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