Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[AhmatAhmatov1959]

Slow drift can be a symptom of two things.

The differential amp is overloaded / railed .... the voltage at the oupuf of the differential amplifier U1 should be fairly constant at around 1 to 1.5 volts. If it is closer to 0 or 2.8 volts then the amplifier is seeing an offset current due to ..

1. Leaky input capacitors ... the DC blocking caps must be high quality film caps C6 and C7. Even a very small leakage current will cause an offset DC votage that will rail the output. The integrator caps need to high quality too. Ceramic caps are way too leaky.

2. Overload input ... the samples from the integrators R13, R14, C4, C5 are overloading the input to the amplifier. If the difference between voltage inputs exceeds 150 microvolt approx then the diff amp will overload. Bad sampling windows will do this.

Hello. I assembled Magpi 3. The speaker produces a constant sound that disappears when the target is brought closer. If anyone has encountered something similar, please help. Sorry for my English

[moodz]

Hello. I assembled Magpi 3. The speaker produces a constant sound that disappears when the target is brought closer. If anyone has encountered something similar, please help. Sorry for my English

Please post some photos of the board top and bottom and we will try to assist.