Can pinpointer detecting thin chain?

[maxm3s]

Nupi Olá, você tem o arquivo no lay-circuito, seria bom!

[Qiaozhi]

Nupi Olá, você tem o arquivo no lay-circuito, seria bom!

Please read the forum rules -> Basic Rules of the Forums
and make your posts in English.

[Fabian]

Hello Nupi. I have a problem: I can not get the voltages you recommend in some zones of the circuit. I set up the board to your specifications, but can not get the 4.5 volts at the junction of R5 and C4. There I have 1.65v. Also at the junction of R4, R5, C3 and IC1 I have v 2.5. With VR2 varies between 1.65v and 2.5v.
The only difference with the instructions, is that I used a polyester capacitor 1.8 nf instead of ceramic.

Any suggestions on how to continue?

Fabian

[Nupi]

Hi Fabian,
I assume that you are measuring with the L2 disconnected.

1--Take the power off
2--Disconnect the entire coil.
3--Disconnect R4 on the side of the emitter.
4--Measuring the resistors R1 + R2 should be about 100K are rotated left or right. Tell me if that's right.
5--Add the voltage back on.
6--And then measure the voltage at the emitter of TR1 to the minus. What voltage do you measure now?


nupi

[Fabian]

Hi Fabian,
I assume that you are measuring with the L2 disconnected.

1--Take the power off
2--Disconnect the entire coil.
3--Disconnect R4 on the side of the emitter.
4--Measuring the resistors R1 + R2 should be about 100K are rotated left or right. Tell me if that's right.
5--Add the voltage back on.
6--And then measure the voltage at the emitter of TR1 to the minus. What voltage do you measure now?


nupi

Hi Nupi.

- Measurement of R1 + R2 is 103K and oscillates somewhat.

- Between the emitter of BC560 and minus, measured 5.1 v

[Nupi]

Connect R4 again and measure the voltage at the immetter. What voltage do you measure now?
nupi

[Fabian]

What is the "immetter"?

At the same point (BC560 emitter), with the R4 connected, got the same volts: 5.1

Fabián

[Nupi]

Sorry, emitter TR1

[Fabian]

What is the "immetter"?

At the same point (BC560 emitter), with the R4 connected, got the same volts: 5.1

Fabián

That's the measurement

[Nupi]

Is good, that means that the error is not in the IC, but in the coil.
I'm afraid you have the coil not connected properly or is not wrapped properly.
1--Please make sure the coil is connected properly.
2--Measure the resistance between L1 and L1a-L2 and L2-between L1a and L2a and between L1 and L2a. What is resistance do you measure?

[Fabian]

Is good, that means that the error is not in the IC, but in the coil.
I'm afraid you have the coil not connected properly or is not wrapped properly.
1--Please make sure the coil is connected properly.
2--Measure the resistance between L1 and L1a-L2 and L2-between L1a and L2a and between L1 and L2a. What is resistance do you measure?

L1 to L1a-L2 (0,35 wire) 1,9 Ohms - 2 mH
L1a to L2a (Two layers coil) 4,2 Ohms (0,28wire) - 2.5 mH
L1 to L2a 5,1 Ohms 3.4 mH

[Nupi]

The values are too high. They should be about 0.6 and 1.6 ohms.
How many layers have you wrapped?
Do you have an inductance meter.?

[Fabian]

I made it as you described in the thread:

71 turns in the first layer (0.28 wire)
74 in the second one
and 54 in the last one (0.35 wire)

I've have a multimeter with H scale

[Nupi]

What is H scale?

[Fabian]

Henries