I have created a PCB that makes a 7 segment common anode display module controlled by shift register
I have soldered the components on a first PCB and it works fine. I have a sample code that displays digit 0 to 9. No problem.
So then I went on to solder components on the second PCB. This was to test daisychainging such modules. And it did not work. I created a thrid one and the behaviour is the same. I tested display a shift register by using the ones from the first board that definetly work and still no joy.
Then I discovered something. When I touch Clock (STCP) the module all of the sudden works . But only for few seconds. It then flickers and dims out.
Can someone explain this behaviour for me and is there anything I can do with this board to fix it. I checked all the connections with multimeter and they are fine. Can this be somefow linked to the way the tracks are layed down on the PCB. This is a learning curve for me. I know that I should not use 90 degrees angle on the PCB and I did not know that when I was starting this little project.
Any help would be greatly appreciated.