Rhesus3000
New Member
I use TLC555 cmos timer.No. The POP sounds do not come from the 555. The sounds come from the outputs of the CD4017 ICs. I think you need beeps, not POPs.
Do you have an ordinary high current 555 that needs supply bypass capacitors that are not shown in your schematic? Or do you have a Cmos low current 555? If you have an ordinary 555 then its 400mA supply current draw each time it switches might be causing the supply to the CD4017 ICs to collapse and mess up the counting.