Lf353 or Ca3240

[ne555]

Hi to all
Can replace for more stability There is no stability with motion Despite all attempts to connect gnd and shielding there is still sound when shaking with all the recommendations of the members Problem with either lf353n The LM308 has a noise connection too??

[dbanner]

Not chip problem. Other problem. Proper shielding problem. Ground balance problem. Reject ferrite? Yes? Then shielding problem. Pay attention to start/finish wires, proper shielding. Bad soil/ground? Yes? Adjust ground balance trimmer until she is quiet.

[ne555]

I think the problem in the board or one of the components tested many coils as well as made DD and concentric and high precision measurement of induction and turns but got the same result in depth not less than 15 cm and instability of vibration I used a USB cable with a shield also did the same problem Output on pin 7 is 4mv I do not know the fact of the problem Remain that some replacement components are probably not genuine or damaged

[dbanner]

Ok, I understand now you mean shaking or vibration causes detector to sound. This should not happen.
Did you use metal shaft for your detector? If so, shaft must also be grounded.

[dbanner]

Also you might try different chips like the TL0xx Jfet opamp TL071/72

[ne555]

Thanks for helping me Yes Use a stick from a metal damaged detector and have 35 cm plastic away from the coil stick exp300 okm The same is the Stick Plus Star 2 i have gnd with it yeah Yes I asked for some replacement pieces from the shop I will replace and display test results here

[ne555]

Please display a lower noise replacement menu lm308 and lf353n BF245C and 2n2907 u have any information

[ne555]

Replaced lf353 with TL062 and 72 and 82 was 82 the least noise and the same procedure on 308 was 081 less noise also and the 100K metal casing gp with gnd not noise now good work ihave to proplem After rejecting the ferrite piece, the aluminum and silver were completely rejected on the DiSk key and the problem is that the depth of the piece of copper coin 2 cm does not exceed 18 cm to 20 cm.Please give recommendations from experts The voltages on pin 7 Tl082 rose became 10mv

[dbanner]

coil needs to be tuned properly. The Rx 16.1khz, tx 14.5khz. take notice of the difference, it is 0.6khz. always try to keep this difference between the two coils. Ok, say your tx is 14.4khz, then your Rx should be tuned to 16khz. See? So that when she is nulled you can get 20 degree phase shift between tx and Rx, now adjust the to reject ferrite and all will be good with silver and the rest.

[ne555]

I do not have any Hz measuring machine and I do not know the points to be controlled whether it is through the volume or measurement of the interference of files u have video process Explain the process

[ne555]

How do I know TX has become 14 khz is it by volts or by induction what is the arithmetic equation my rx 6.5mh 18 ohm 0.3mm copper tx 6mh 24ohm 2.5 copper

[dbanner]

Your coil is with correct inductances so everything should be fine so long as you null properly. I think your nulling is slightly off. By what method you null coils? Do you have oscilloscope?

[kt315]

I think your nulling is slightly off.
--
i think he does not understand the role and importance of right shielding of coil and housing.
look on his words 'There is no stability with motion'. on a table, in static, all are ok.
but if you move coil and himself in movement you get an electrocstatic charge just only you begin to move.
its ordinary trouble of all beginners - they do not sure appreciate of right shielding and get the unstability.

[ne555]

The sound problem with an extended swing is now fully stabilized after replacing some pieces and making ground on the resistor casings I have no oscilloscope shielding tape Adhesive paper under aluminum wire wire 05 mm Nude on the shield shield connector Shield good with bare wire Problem now with rear coin coin Diameter 2 cm Do not exceed 18 cm depth, according to what you see from the videos should be up to 35 cm means I lose half the depth almost

[ne555]

. By what method you null coils
No understand your question sorry my English not good