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coil builders
Topic Started: Tuesday 26-01-2010, 08:55 (279 Views)
silverback
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Hi All. i have a minelab 8" coil i picked up a while ago.it has been played with and i would like to know if anybody can help me.the lead coming from the coil has 2 wires plus a shield,it hs been cut and joined with 1 wire the the top cable and the second bottom wire has been joined with the shield and joined to the shield on the topcable. Ihope you can follow this. in the connector up top it looks like allthe connections have jumper wires on them. there are 4 scenarios that i can think of
1 its a dd ^o)
2 its a mono ^o) ^o)
3 its an ai(salt coil) :blink:
4 it is a complete stuffup :D :blink:
as you can imagine i am not game to try this thing on my detector, any body got any ideas?
All the best,
Peter
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davsgold
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Peter, I think you will find that the old model Minelab coils were built that way, with a join in the coil cable about 10" or 12" above the coil.

I think that with the jumpers in the plug that you talk about were for a mono ? carn't quite remember.

Wether it has been played around with I am not sure, but there were ML coils built similar to what you describe.

cheers dave
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silverback
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Hi Dave,yes the join is about12" above coil,just that the soldering did not look all that professional and 2 different coloured cables.Oh well i will try it on one of the 2100s before the 3000 or 4500.thanks again for your replies.
All the best,
Peter
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davsgold
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silverback
Wednesday 27-01-2010, 08:39
Hi Dave,yes the join is about12" above coil,just that the soldering did not look all that professional and 2 different coloured cables.Oh well i will try it on one of the 2100s before the 3000 or 4500.thanks again for your replies.
G'day Peter

It may well have been altered then, the ones I've seen are black cable above and below the join. The wire thickness changes above the join on the ones I've seen.

The later ones that came out with the GP 3000 etc were all the one cable with no joins. I believe the ones that came out with the SD model machines were the ones that had the join.

cheers dave
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Topcat
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Hi Peter,

Find attached a diagram of the plug connection wiring for the Minelab SD/GP ML coils.

Cheers

Ted
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Attachments: SD2100_Coil_Plug_Connection.jpg (47.61 KB)
Cheers,

Ted


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davsgold
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Topcat
Wednesday 27-01-2010, 16:45
Hi Peter,

Find attached a diagram of the plug connection wiring for the Minelab SD/GP ML coils.

Cheers

Ted
G'day Ted

Is this for a mono or DD coil. Do you know the purpose of the bridging.

cheers dave
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Topcat
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Hi Dave,

It is for both & since the one Pete has I'd say it is a mono because I didn't think that ML brought out 8" DD's
& I have a Minelab 8" Mono & it has a cable join about 12" up from the coil.
You will have to ask the experts on the bridging as I haven't done any coil manufacturing myself.
The difference between the mono & dd is in the wiring setup in the coil.
Cheers

Ted.
Cheers,

Ted


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www.havewheelswilltravel.iinet.net.au
"I believe that if life gives you lemons,you
should make lemonade & try to find somebody
whose life has given them vodka, & have a party"!!!!

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silverback
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Hi guys,just pulled the top connector apart again and the wireset up is-shielding wire comes in at number 1 and jumps across to 5, centre wire comes in at 4 and jumps to 3 then 2.does this help with the diagnosis! :'( :D from my understanding of coils is it correct that with a mono a signal is sent down 1 wire and received back by the other wire and with dd the signal is sent then turned off to listen for the reply albeit many many times per second.?
Edited by silverback, Thursday 28-01-2010, 14:11.
All the best,
Peter
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davsgold
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Both DD & Mono coils have the pulse sent and received many times per second, hence the term pulse induction (PI) also dual voltage, all a bit hard to understand for me, so long as it works is what I care about.

I think it is the DD coil that sends the pulse on either or both? windings and receives on the other, and the Mono coil has only one winding around the out side edge, so it sends and receives on the same winding many times per second, alternating between sending and receiving. Damn amazing I reckon, and no wonder it's all a bit hard to understand.

It's a bit like driving a car, you don't need to be a mechanic, though sometimes a little knowledge helps and sometimes I think it also makes it worse. ;)

cheers dave
Edited by davsgold, Thursday 28-01-2010, 18:38.
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