R30 value

[Gavinius]

I'm testing an HH revC1.11.05, VCO built yesterday.
I've noticed that R30, in part list, is 39K while in the VCO schematics is set to 150K.
Which is the correct value?

[Carl-NC]

150K

[Gavinius]

I tried with both values, but I managed to work the threshold pot only with 39K resistor.
With 150K I can't set speaker to silence, I always get a costant noise and seems that rotating threshold pot both sides doesn't change anything.

[Carl-NC]

What are your values for R31, R32 & R33? Double check them.

- Carl

[Gavinius]

What are your values for R31, R32 & R33? Double check them.

R31 100K pot
R32 100K
R33 100K

I checked all resistor values around IC8b and seem to be correct; threshold works only with R30=39K or less (I actually use 33K).

- Francesco

[Carl-NC]

Yup, those look right... doesn't make sense, R30=33k should mean that the output of IC8b is hard negative, and you would only get silence. Is the autotrack switch closed? What opamp are you using for IC8?

- Carl

[Gavinius]

Yes, autotrack switch is closed and IC8 is a TL082.

However, with R30=33K, the metal detector works, it can detect 50 euro cent coin at about 15-20 cm.

Is quite unstable, when I get my hands close to the circuit or the coil I get a signal in the speaker.

Tomorrow I'll probe some test points with the scope and post the waveforms to ensure that all is correct.

bye
Francesco

[ma330]

help to me

hi too all.
ibuild bandido umax.but
i not found icTLC 2262 & mc33178 &2931a ..please bring forward to me similar ic for those.
please help to me. tank you . wait for you. good byyyyyyyyyyyy

[Qiaozhi]

Bandido II uMax

hi too all.
ibuild bandido umax.but
i not found icTLC 2262 & mc33178 &2931a ..please bring forward to me similar ic for those.
please help to me. tank you . wait for you. good byyyyyyyyyyyy

Hi ma330,

I have replied to you several times on this subject, but you keep asking the same questions on completely the wrong forums, and under the wrong topics. Please use the Silver Sabre / Bandido forum, where you will probably get a response. Otherwise you can search for my previous replies on this subject.

[ma330]

help to me

hello :
i build bandido II umax.but I have many problem.i want from you that if you can help to me. please...

1.i not found icTLC 2262 & mc33178 &2931a ..please bring forward to me similar ic for those.

2.in board in 5 capacitor in cognito.i send for you one photo from board .in photo specified capacitors with blue color.please give to me deal those.

3.are all diods 1n4148???????????????????????????????????

4.i want data about coils.deal and turn...number wire ....diagonal coils.???

5.please give to me data about amount detect exampel: a coin ....discriminant metals
exampel: iron&gold...depth????/??

6.you can send for me a photo from board aucmented this circuit???????please send for me.

7.have this circuit auto tuning???

8.maximom this detector for detect ????????????????????????????

thankful from you and appetent good nice for you.

wait for ask you. good byyyyyyyyyyyyyyyyyyyyy

[Gavinius]

ma330, sorry but I can't help you; maybe if you post in the right section and in the right thread someone can help you.

Today I took some pictures of waveforms in variuos TP.
The Oscilloscope was a B&K precision 15MHz.
The channel was DC coupled and ground was always in the screen center.

TP1:
Master clock, about 1000Hz, pulse width 70uS

hor: 200uS/div vert:2V/div

TP2:
Coil signal, inductance is 498uH with a dump resistor (R11) of 680Ohm.
The coil is shielded with kitchen aluminium .


hor: 10uS/div vert:20V/div

TP3:
Clamped coil signal, as you see there is a sort of unwanted positive "slope"

hor: 10uS/div vert:0.5V/div

TP4(1):
Amplified signal, just after front-end NE5534 amplifier.
It's well visible the secondary sample, and a lot of noise.

hor: 50uS/div vert:1V/div

TP4(2):
A closer view at TP4

hor: 10uS/div vert:1V/div

The voltage on TP5 is almost DC with a slightly positive value (0.17-0.18V).

Are these waveforms ok?
Any suggestion or comment will be greatly appreciated.
Bye

-Francesco