Schmitttrigger doesnt work

[JuculianD]

Hello!
I am not very experienced in the use of schmitt triggers (experience=0) and designed a circuit.
For my application, I need 3 channels but I don't want to have an inverted signal.
I have used a 74HC14D (NXP) which has 6 channels.
To not have an inverted signal, I have connected the output to the input of an other channel of the chip. Therefore, in my theory, the signal should be inverted again.
It is not a nice solution, I know, but I thought, I could just use those 3 spare channels because I don't need them anyway and save using an inverting circuit.

BUT!
It doesn't work.
I have made some PCBs and tried it out, but no matter which input signal I put in, the output is high all the time.

Can somebody help?
Is my circuit not possible, or ist the error somewhere else?
(I am using it in my 3D Printer, maybe I am reading it out wrong. I will make some measurements now.)

Thankyou very much!
Julian.

[retrolefty]

Wiring diagram appears correct. Nothing special about schmitt trigger so better check your testing procedure or test equipment usage.

Good luck 

[JuculianD]

Thank you very much.
You are making me couragous, because I was quite sure that my circuit is crap  .

I will test it now and give feedback soon.

[JuculianD]

You are right!
It works as it should .
There is something wrong with my chinese crappy board, it is too bad engineered to compare 0,00V to 5,1V  .


Thanks for all the help,
the thread can be closed.

[MarkF]

Glad you have it working.

You might consider a cleaner trace routing:

   

[JuculianD]

Oh, yeah.
I dont care about the schematics, but the PCB looks odd.
I must admit, I was just using the autrouter...


Thank you for your help,
this forum and Dave's videos are helping me a lot