fisher 1210x pot adjustment/setup question

[jameselectronic]

hi to all,
i have recently dug out an old 1210x that i used a few years back when detecting with my dad, it was in a bit of a state but after changing the on/off/descrim pot and a bit of general soldering/rewiring shes as good as new. i have tested the macine the last couple of days on some target coins and im not sure its working at optimum performance. i have adjusted the sensitivity pot behind the headphone jack just to the point of no chatter and its prob detecting 3 to 4 inches on a copper penny in air. can anyone tell me what the other two pots do on the board or if there is a sure fire setup procedure to ensure optimum performance?
thanks
james.

[Qiaozhi]

hi to all,
i have recently dug out an old 1210x that i used a few years back when detecting with my dad, it was in a bit of a state but after changing the on/off/descrim pot and a bit of general soldering/rewiring shes as good as new. i have tested the macine the last couple of days on some target coins and im not sure its working at optimum performance. i have adjusted the sensitivity pot behind the headphone jack just to the point of no chatter and its prob detecting 3 to 4 inches on a copper penny in air. can anyone tell me what the other two pots do on the board or if there is a sure fire setup procedure to ensure optimum performance?
thanks
james.

I've got one of those!
The schematic is attached below:
From left-to-right the pots are ground balance, discrimination, disc bias and audio threshold.

[jameselectronic]

thanks, i have had some nice george IV coins with it in the past, unfotunately i decided to "twiddle" the other two pots just a bit and im now worried the ground balance may be out, being a nube to the technical side of metaldetecting is there a sequence i can go through to ensure the ground balance set up correctly?
many thanks,
james.

[jameselectronic]

I also have the remains of a 1265x that would need a lot of workto get back up and running, just wondering would the spider coil from it be of use on the 1210x (depth/accuracy)?, i measured the resistance on the 1210x coil and both loops measured 40 ohms, but on the spider coil one loop measured 42 ohms and the other 4.6 ohms so maybe its kaput? i know some detectors are not compatible with other coils, just a thought.

[Qiaozhi]

thanks, i have had some nice george IV coins with it in the past, unfotunately i decided to "twiddle" the other two pots just a bit and im now worried the ground balance may be out, being a nube to the technical side of metaldetecting is there a sequence i can go through to ensure the ground balance set up correctly?
many thanks,
james.

You can set up the ground balance using a small ferrite slug. Set it to reject the ferrite.
Audio threshold is easy. Just set to almost silent background.
The DISC bias sets how hard the detector tries to discriminate.
The DISC pot is on the front panel, and I expect you know how to use that.

I also have a 1266-XB, which is similar to the 1265-X. The coil on the 1210 is permanently wired to the control box, and is not compatible with the spider coil.

[jameselectronic]

Great, thanks Qiaohzi, i will try that, i have ferrite cable blocks for electronic noise reduction somewhere ill dig them out if they are the correct thing and post the results tomorrow!
many thanks,

[ApBerg]

I've got one of those!
The schematic is attached below:
From left-to-right the pots are ground balance, discrimination, disc bias and audio threshold.

Hello Qiaozhi,

You have a Fisher 1210 ? I made a pcb from it... never made it in real so there can be errors in it !. I had in mind to make it for the grandchilderen to use it as a light wight detector on salt sand beach, it must go (long) on one 9v batt..?

Is it worth making it you think ??

Best regards.
Ap

[Qiaozhi]

Hello Qiaozhi,

You have a Fisher 1210 ? I made a pcb from it... never made it in real so there can be errors in it !. I had in mind to make it for the grandchilderen to use it as a light wight detector on salt sand beach, it must go (long) on one 9v batt..?

Is it worth making it you think ??

Best regards.
Ap

I think it would be good to make one for the grandchildren. It is very light, unlike the later Fisher models, and only uses 1x9V battery. It has the same type of discrimination as the old Rimatron and Viking detectors, which is not so good. But should be ok for the kids. It has a fixed discrimination setting internally (the Disc Bias), and the Disc control really only controls how hard it tries to discriminate. I modified mine to discriminate against iron on the minimum Disc setting. However, I doubt it would be much use in wet sand, and they would have to stay in the dry areas.

[jameselectronic]

i remember my one was terrible on the wet sand just kept crackling and buzzing constantly, more of a land lover

[ivconic]

What are coil data for 1210?

[ApBerg]

Hello Friends,

Thanks for the info, ...start making one I think, see how it works. (if ..it works )
Hello Ivica, for coils I think that the 1260 family coils work ? some 4.1 kHz?
look at: http://phazitron.narod.ru/archiv/sch..._1260_Loop.gif

Best regards.

Ap

[ivconic]

Hello Friends,

Thanks for the info, ...start making one I think, see how it works. (if ..it works )
Hello Ivica, for coils I think that the 1260 family coils work ? some 4.1 kHz?
look at: http://phazitron.narod.ru/archiv/sch..._1260_Loop.gif

Best regards.

Ap

Is it?
For 1265 and 1266 are quite different data...
1260 is quite different.
1210....? How can be sure?

[ApBerg]

Is it?
For 1265 and 1266 are quite different data...
1260 is quite different.
1210....? How can be sure?

Hello Ivica,

No... I am not sure that the coil from the 1260 will work... but thats the fun it must not be to easy..
Just looking at the internet for some info... found:

http://www.fisherlab.com/hobby/dave-johnson-essays.htm

Very nice info, take a look at it !

Best regards !

Ap

[ivconic]

Pay attention on "Question 5" here:

http://www.fisherlab.com/hobby/davej...rinterview.htm

[ivconic]

"One of these days I may have to eat my words about “halo effect”."

Question 10....
Tough to be smart about that....
Dave come to my place and i show you hallo effect proofs.
You can't expect to meet hallo effect on "young" soil with "young" targets.
Here we have finds 2800 years old, while there you can have barely 300 years old finds!
How the hell you expect to meet real "hallo" there!?

Sorry for me slipping off topic here! Couldn't resist! Very interesting interview!
Thanks Api!