Superscan PI

[ZOUjiarui]

Hello everyone, I need help from those who have successfully obtained the desired sensitivity. I'm unable to achieve the highest sensitivity setting. The inductance is approximately 520uH, 1.2R. Thank you very much.

[ZOUjiarui]

There was no smoke or significant heat generation; awaiting coil testing.

[ZOUjiarui]

The voltage should be between 4.8 and 4.9 ohms for normal operation.

[nasios]

The drawing is custom made for Qiaozhi

Hello, you have the complet schematic and the other part?

[Hassanp]

Hello, my dear friends, thank you for your reply. I have the frequency of 90 Hz on the base 3 oscillator and the base voltages are 5 volts positive and 5 volts negative, 24 volts positive and 12 volts negative on the board and there is no problem. I will inform

[profesor]

I am asking friends who have succeeded in building this circuit to help my circuit work and I will give a great project for free to a friend who helps.

I assume you have the necessary measuring instruments to operate this circuit.
oscilloscope .multimeter etc.
1-Before connecting the coil, check the +5v,-5v,-12v,-24v lines. Are there the required voltages?
Check the 3rd leg of the 2-pulse generator 555. See the approximately 90hz pulse signal on the oscilloscope.
3-Make a test coil of approximately 380uh 2R 20cm in diameter and connect it to the circuit with an RG58 cable.
If you have assembled the 4-circuit correctly, connect the TX end and RX end with the coaxial cable.
5-Connect the first channel of the oscilloscope to the output of LM 709.
6-If everything is OK, you will see the signal. Adjust the signal so that GND is in the middle with a 100k trimpot.
Connect the second channel of the oscilloscope to the output terminals of the 6-4538s and see the sampling signals.
7-If everything is correct so far, you should see the metal detection signal on pin 7 of the TL072 opamp on the second channel of the oscilloscope.

[GeoMax]

Hi Hassanp,
I don't have a working circuit board. But I've looked at the various schematics here in these posts and they look good at first glance. I couldn't see any obvious errors like you see in other circuit diagrams on the internet. I have not checked every IC pinouts. Many times people write wrong pin numbers at the ICs in the drawing. Have you checked them aginst the manufacturers datasheet?

[Hassanp]

I have a lot of respect for Almanah, they are good people, my friend, if you have a correct design of this device, please send it to my email so that my problem can be solved.

[Hassanp]

I built the circuit by hand according to the schematic. Do you have the schematic or pcb that is healthy and working and can you put it for me?

[GeoMax]

Hi Hassanp

Which of the 3 or 4 known Superscan schematics was your base for the project? And further... which PCB layout did you use? Probably there are also several floating around in the Internet.

[Hassanp]

I am asking friends who have succeeded in building this circuit to help my circuit work and I will give a great project for free to a friend who helps.

[Hassanp]

Well, the schematic of the circuit did not match with the pcb that my friends placed, for example, the bases of the MOSFETs j112 and j113 were shifted, and for example, the power supply line in the vco part of the sound was wrong, and in the doubler part, the voltage +5v and -5v, unfortunately, there were mistakes, for example, instead of diode 4007 instead of 4148 It has been used and a number of others. I mean, has anyone succeeded in setting up the circuit with this schematic, and if there are any special modifications, please post them so that I can set up the circuit. My circuit is still in trouble and does not have a metal sense. please help

[GeoMax]

Hi Hassanp,

what kind of "problems" have you solved? Maybe you have "solved" to much and that's whay the circuit is not working anymore. You should give us a little bit more information's of what you did.

[Hassanp]

Hello friends, I made the circuit and solved many problems, but unfortunately the circuit does not work, I have a beeping sound and the threshold volume works, but it does not work when the metal is close to the sense metal coil. I give

[Carl-NC]

Looks like it varies the charge rate of the timer RC based on the signal level from U8b. Don't know what that means in terms of the generated audio, though.