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555 timer help

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New Member
Hello guys
I'm in middle of my project presentation, I have build an electronic bird repeller using two 555 timers. The first 555 timer produce the required frequency of 250Hz but the second 555 timer doesn't give any output on the oscilloscope although on the simulation (Using Proteus) everything is okay.
I've attached the picture of my prototype. I really need your help.


Well-Known Member
Most Helpful Member
Welcome to ETO!
It's difficult to help without a schematic and sharp well-lit pics of both sides of the pcb.


Well-Known Member
Most Helpful Member
Exactly what do you expect us to do with a picture of 40 components? If I send you a picture of my lawn mower, will you tell me why it doesn't run? THINK. This is an electrical engineering forum. We don't even burp without a schematic.



Active Member
Show us the proteus schematic or a screen capture of the proteus running on PC that works. May be then you'll get more help from others.


dr pepper

Well-Known Member
Most Helpful Member
Do you have a 10nf to ground on pin5?, some chips need it.


Well-Known Member
IC's seem to be missing bypass caps..
Hard to tell but one timer seems to have no trace to pin 8 (VCC).
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