No Sound from Delta Pulse Sniffer PCB – Need Help

[lahceneredouane22]

Hello everyone,

I have built a Delta Pulse Sniffer PCB, and I have attached both the PCB design and the assembled board. However, when I connect the power supply, nothing happens at the speaker—no sound or response at all.

I have checked:
✔ Power connections (+12V and GND)
✔ Component placement and soldering
✔ IC orientations

Could anyone help me troubleshoot the issue? What should I check next? Any advice would be greatly appreciated!

Thank you!

[Detectorist#1]

Hi,
It is very complex to help you when all parts are soldered on the PCB and no right result. This project is not for beginners in this area. My advice is - look for near "hardware master" for help. Will be very hard to receive useful advices in the forum.

[lahceneredouane22]

Thanks for your response. I understand that troubleshooting a fully soldered PCB is complex, but I have enough experience in electronics to handle it.

The issue I'm facing is that the Delta Pulse should emit a startup beep, but in my case, it doesn't. However, when I manually apply a 12V signal through a resistor to pin 3 of the NE555, the buzzer works. This suggests that the NE555 is either not receiving the correct trigger at startup or its surrounding components are not functioning as expected.

[Detectorist#1]

Where you read that Delta Pulse Sniffer have to make startup beep, I'm not sure for this. The pin3 of 555 is pulse output - in this case ALL signals before 555 are under doubts

[Emersonpaz]

There is no startup beep, can you check if the coil is oscillating? If you bring your ear close to the coil you will possibly hear a buzzing sound.

[Emersonpaz]

tried replacing the 555 audio?

[Detectorist#1]

The input pin of 555 in this design is pin No 7 not No 3. Maybe this IC is in reverse position. Check this.

[Carl-NC]

Could anyone help me troubleshoot the issue? What should I check next? Any advice would be greatly appreciated!

Do you have an oscilloscope? Start at the transmitter, verify it is working. Continue with the preamp, demods, etc.

[kt315]

[kt315]

[kt315]