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hello, to adjust my nulling are what I have to favor the late 20 degrees BETWEEN TX and the output of the LF353 or lower then the voltage on the output of LF353?
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I usually null by disconnecting the RX completely from the board.
Then connect straight into a scope. Tune for min signal.
The 20 degrees is measured from TX on one channel to RX on the other but it's
tough to measure with any accuracy... -
Set your geb pot half way
adjust the overlap so the machine stops seeing ferrite
see if it gets gold bronze and silver
see if you have a single beep on the pass
take a peek at the preamp output if its 300mV pp or better
pot it
may need tiny tweak during potComment
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ok thank you for the advice with the oscilloscope I can not have 20 degrees of delay I Still more than 20 degrees .
if I leave the knob in the middle, some copper coins position are not detected, so I obbligé turning the knob of ground effect to the right to retrieve the money.Comment
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Set your geb pot half way
adjust the overlap OF YOUR COILS - to the point where the machine stops seeing ferrite _ this now the CORRECT initial phase.
see if it gets gold bronze and silver as quick test.
see if you have a single beep on the pass - this means the Rx coil is the correct way around - two beeps means you will need to flip Rx coil connections - at coil end..
take a peek at the preamp output if its 300mV pp or better
then pot the COIL in potting resin -
may need tiny tweak of coil location during pot - in order to maintain Ferrite rejection...Comment
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