IDX-PRO+VDI

[der_fisherman]

Pot were supplied by silverdog and are linear.
When I said iron goes first, I meant after coins and pull tops are discriminated. Coins are first to disappear.
I think the schematic off silverdogs site and other diagrams are correct, at least they mostly correlate.
Could I be looking at a problem with the Fisher coil? Frequency/phase angle
Ivconic seemed to get it working, maybe he has some experience with this issue.

Regards,
Max

Have you tried swapping the connections to one of the two coils?
Just a thought!
Andy

[eduardo1979]

The scheme is correct, the Silver Dog PCB are correct. This detector works well with Whites coils 6000, XLT, etc and with the coils have been constructed DD manually. With solenoid Fisher also works well if properly set the resonance frequency and the phase angle. You have to look for suitable condensers for coil Fisher.

[maxfly]

Pot were supplied by silverdog and are linear.
When I said iron goes first, I meant after coins and pull tops are discriminated. Coins are first to disappear.
I think the schematic off silverdogs site and other diagrams are correct, at least they mostly correlate.
Could I be looking at a problem with the Fisher coil? Frequency/phase angle
Ivconic seemed to get it working, maybe he has some experience with this issue.

Regards,
Max

[golfnut]

Did you supply one or both pots?? If so,

Check if the pots are Linear or Log response. A log pot wont do much early on then bunch up reponse as value changes hugely with rotation.


See if you get 1/2 res val at mid throw etc.

Increasing disc pot sees iron go first

This sounds correct to me

Are Disc and Geb labelled correct on drawing?

S

[maxfly]

Hi golf nut,

I have made connections according to this diagram:

http://www.geotech1.com/forums/showthread.php?t=18051&highlight=Idx&page=24

Both gb and disc connections check out with the schematic,

Max

[maxfly]

Thanks for the reply Qiaozhi,

If I adjust the gb using a ferrite rod (10x40mm) until there is only a slight noise when waving it 10cm above the coil then with the disc pot in least disc position, all coins are not detected nor is aluminum pull rings. Iron and al foil (20x20mm square) are still detected. Increasing disc pot sees iron go first then much further around foil goes.

Not only is the disc off scale but also eliminates items in the wrong order!

Max

[golfnut]

All coins and steel are bunched up together and are the first to disc (about 1/5 turn of pot), then lead goes next with foil and alloy go at 2/5 turn on pot.

Are you sure the pot is wired the right way around?

S

[Qiaozhi]

With GB backed off ...

What do you mean by "With GB backed off"?
If you haven't ground balanced the detector correctly, then the DISC settings could be completely wrong, which appears to be the case from your description.

[golfnut]

If the Disc pot is the one which is 25k and the action is over 2/5 travel that is 10k/25k


pull it put a fixed 15k above it, and put a 10k pot in.

Or if its the other one at the bottom, do same trick

S

[maxfly]

Disc issues

Well Fisher CZ-d3 coil has arrived and in general has not disappointed,

With GB backed off can detect a large coin at 42cm.
Pin point works well.
Sensitivity fine.
Disc not good (most important to me).
All coins and steel are bunched up together and are the first to disc (about 1/5 turn of pot), then lead goes next with foil and alloy go at 2/5 turn on pot.
is there a method of stretching out the disc function and or adjusting it.

Max

[golfnut]

would making this det a full wave demod give clearly better performance?

Anyone up for it.

S

[golfnut]

It looks like the pinpoint Channel, and Disc are ON all the time.

When you want Pinpoint it turns the Disc OFF.

Is this right?



Is it better to have for..

Disc - disc / geb ON for normal use - Pinpoint Channel OFF

Pinpoint - turn OFF the Disc Ch and Pinpoint Channel ON

Steve

[golfnut]

In normal operation, which channels are ON with the IDX?

S

[eduardo1979]

hello all,
Last week I got my original coil. the bluemax950. But even with this my idx does not work. But I can not find fault. pinpoint because if I hit, I can hear a tone. when I turn the treshhold, this tone louder. I measure the correct frequency on tx-connection. changes in the last layout I did not yet. are the parts would still be the first layouts in there.
maybe someone has an idea? or can give me some values that I can measure it in the circuit?

regards, marc

You have to replace the resistance of 47 ohms for a 1K potentiometer. Your LF 347 has too much gain and so gives a constant sound. Happened to me just like you. To put a potentiometer 1 K, you can adjust the gain so allows.

[golfnut]

Im not sure how this works - Im making one but its not ready yet..

I cant work this one out..


If you look at schematic..



2 modes of operation - Switch open or Closed.

A - closed MOS switch - ALL Three channels running
non motion pinpoint CH, GEB, DISC

B - open MOS switch - GEB and Disc Channels Unconnected


Looks like in Normal Disc mode the non motion (noisey) CH is live too.


I may very easily be wrong though!
S
ps that pot is 10k
Beware on this the supplies are a bit odd - The Battery 0v is effectively -4v NOT GND

Ground or the potential of the sheilds is at 1/2 of the 8volt rail or +4V