Interesting Modified SDC2300 On Gumtree

[Bush]

Cheers - AuMan,
`i` really appreciate the circuitry tips..
Had a feeling that the two carbon shield plates needed to be isolated from each other around the coil edge regardless that their connections merge together up the track.
My feelings on the coated cardboard is Fubar ( tango & cash ) F-up beyond all recognition.
It`s hard to believe the original carbon coatings are so thin including the cardboard.
Earlier `i` mentioned `i`ve ground up filtration carbon for the PVA carbon glue mix.
New cardboard is cut / folded and ready to go.
In testing the mix the glue seems tobe restricting the carbons conductivity.
Which makes me think activated carbon from the Brewery shop could be the go.
It dries sticky from memory and may add more of the grounded filtration powder to it.
`i` heard on the grape vine that Stainless Steel Mesh may work as a Faraday shield.
but i`m not shore 4 shore.
Could possibly introduce it between the carbon coats.
304 or 316 marine grade and wondering if it`s Austentic ??
Sort of makes me wonder if any other non -magnetic plate-ing could be used which could ``Possibly Improve `` the Coil Performance.
Doubt it though MineLab Techno`s Researchers would have done The Calc`s.

The SDC Curly Cable is FUBAR too.
Previously i did tried heat on the outter sheathing to straighten it `but` failed as it is the inner white cable that keeps it sprung & curly.
Coiltec cable `i` now realize is two core multi strand wire both have shielding and an additional insulation coverings. .
The SDC cable is quit different in it`s composition ,number of strands , AWG and sizes.
One thing i can do is use the Coiltec cable joining the 2 desperate shielding wires together to mimic the SDC cable.
`but` A BIG BUT on what outcomes will occur with both wires shielded by the same wire.

Hopefully an Enthusiasts on P/A with some knowledge could place some Potentials Outcomes could input here . ????
Pic attached.

 

[AuMan]

Hi Bush,

So to hook that one up, the thicker wire is for the main windings.
The outter of the smaller wire is for the shield and the the inner, connect that to the winding that the inner of the other cable connects to. This will be for the RX.

Then at the plug, the two outter wires are connected together and connected to the 2 ground pins.
And the I'll have to get back to you on the pin numbers for the TX and Rx.

Make sure you get all of the wires to tin properly as I assume the wires are enameled.

For the shielding, you should have used some hot air to make the tape let go easily.
Don't use mesh. Aquadag is generally what is used on coils, about 90 ohms/inch.
Test it by painting 2 wires(or more) onto some card and coat it, let it dry, then measure the resistance between the 2 wires.

Whether this works or not remains to be seen! Coil building is a black art and getting everything right for a coil to work properly is really difficult. And getting a coil good enough to work on a supped up machine like the SDC is even harder.

But hey, you've come this far and you have nothing to loose and only knowledge to gain.

Cheers

 

[Bush]

News Update.
Minelab SDC2300 ``8``inch Original Coil Repair.
For those that maybe interested.
Just bench tested what i`ve put back together and getting positive results.
Procedure.
Cut new cardboard for Faraday Shields out of disposable dinner plates.
Sprayed PVC glue over cardboard.
Sprayed ground down Filter Carbon Activated Charcoal over pvc glue with spray gun.
Let dry for a while.
Re coated again with liquid brewers activate carbon brushed on this time as it was a bit lumpy to spray and let dry.
Installed shielding wires then re coated those wires with the liquid carbon & let dry.
Sprayed over the cardboard shields again with a thin mix of contact adhesive and thinners to bind the carbon surface.
A basic Re-wire job with new straight cable.
Plugged in turned on.
Hey Presto.
It Works.
``i` can`t believe it.

 

[Bush]

 

[Bush]

Photo of Assembled unit.
No it`s not a Hoax.
Brief testing.
Unit seems OK.
Setting 2 Unit stable and responding to targets
Setting 5 Unit stable and responding to targets.
Regardless of the Ohms variation on the modified / replaced Faraday Shields in the photos above in previous post.
The Unit and coil seems tobe responding as it should.
Early stages i know and more testing needs tobe done.
What i thought i noticed was a decrease of ferrous targets yet copper and lead seemed good.
Whether that is a possibility i`m not shore.

Any comments on the increase of Shielding Ohms from the modification of this coil and potential outcomes would be appreciated.
Woody , Geecky , Mr Jones .Maybe Minelab could come to the Party for comment.

Plug connections.
Number 1 and 5 are bridged at the plug and soldered together.
Number 1 = Multi strand cable unsheathed.
Number 5 = Thin cable Coiltec Yellow or Minelab Blue.
Number 2,3,4 are bridged at the plug and soldered together.
Number 3 = White Sheathed cable.
With the Coiltec cable i Twisted the 2 multi strand wires of each cable and soldered together at both ends.

 

[Bush]

Hey Folks ! ~~ No one came to the Party ? ha ha ? Bad Blog ?
How Sad.
I know not many enthusiast out side of a few Professionals have any idea what to expect with the variation of Ohm`s readings from the Original Coil Faraday Shielding
& my back yard repair job.
Original Coil 0.21 ( ohms ) compared to modified ( 7.23 ) over the width of the coil.Variations Extreme.
Big Extremes Hey.

Yeh ~ `i` did receive a Private E-mail message on the potential outcomes on the Extremities from a Pro relating to variables of Ohms readings to my cheep repaired coil.
He`d prefer not tobe identified on P/A my guess in relation to the Coil expectancy`s .
Uncharted Territory my guess.
Tested Coil again `` again ferrous objects seems tobe minimized in target presentation.It does pick up larger iron targets at depth. 1 meter even.
Mainly smaller targets in Non -ferrous seems tobe more presentable.
Is it possible Discrimination with a change of Faraday Shielding Ohms. ????
F-NOSE.
Um `` i did however receive signals on a copper target pretty small around 1/2 a gram @ around 75mm to 100mm.
Not shore really if that is better or worse depth results on Copper Targets using a SDC2300 or pretty much the norm ?

 

[Ded Driver]

hey Bush, you've learnt something & taught us that a repair can be done.
Im sure a few will be keen to see the results in the field if it's successful or not.
Im curious.
Keep posting, you have nothing to lose :Y:

 

[Guest]

I'm curious as well as my original coil is falsing with the slightest downward pressure on it.

Minelab inspected it and was told I would need a new one. $550 or $700 installed.

I took option C. Bought two Coiltek coils for SDC.

Cheers

RS

 

[Bush]

I'm curious as well as my original coil is falsing with the slightest downward pressure on it.

Minelab inspected it and was told I would need a new one. $550 or $700 installed.

I took option C. Bought two Coiltek coils for SDC.

Cheers

RS

Hey #88 Retirement Stone,
Hope the Coiltec Coils work out for you.
Had considered that as a back up plan.
AuMan i thought recons that one of the sadie coils worked. ???
Had i took his advise & bought Aquadag this repair job might have been closer to the original specs.'
Just used what i had laying around which was granulated carbon so gave it a go.Conductible -Non Magnetic.
Probably should have tested the ohms first.
Over did it too the first carbon single coat looked great just when i used the liquid activated stuff it got gummy..& a bit thick.
No big deal if it doesn`t work out i`ll peal it apart for repair & do something different again.

Also i could only locate Aquadag from the UK at an absorbent price for 30 grams plus excessive postage fees.
Fact is the most difficult part of the operation was probing the coil covers apart & slashed my fingers a bit with the Stanley knife.
More so ; as i had previously tried to open the coil then retreated & resealed it with AVS 501 polyurethane glue.
F`n good stuff that is & Petrol resistant.

So consider the Operation if your ok with micro surgery soldering or leave the original cable without re-instating the pin plugs at the other end.
Other than that if you were going to discard the Original Coil i would be interested to purchase it as i have another hair brain idea i`d like to venture into.
Mean while i`ll take this coil back down the beach and use my original test results with the 12``NF for referencing previously mentioned earlier on this post.
Cheers.
Love this Rain.

 

[Guest]

Hey mate.

I might have a go to get inside to see what's loose first and see if I can solve the puzzle.

Cheers

RS

 

[Bush]

~ Warning ~ Content may Offend Viewers. :argh:
~ Warning ~ Modify at your own risk.
Internal Plug Connection Changed and Unit with Coil Tested Successfully.

Standard SDC 5 pin mini star type male plug.
to
Standard GPX 5 pin male round coil cable to unit connection.

Glitch in the system. : :lol: ( more Pics Coming .)
You can also see the re-glued Emi or Emf Filter cylinder thingy that was detached causing a rattle and grief earlier mention on this Post.
Most likely dropped or excessive abuse by someone previously. Frustration on a Hot Day `i` could understand why. ] ]

 

[Bush]

Here it is .

The unit to cable connections nicely tucked away and cover sealed.
Just a couple of extra screws to attend if when the change over to other coils is needed.
I can live with that.
No more false signals or interference from the sensitive plug cable joins.
In this case too being sdc2300 a previous adapter lead had been installed to swap over to GPX plug size.
Why Minelab adopted the mini pin plugs on the sdc and not the gpx plug only minelab can answer.
Why Minelab adopted the mini headphone socket outlet instead of the GPX head phone socket only Minelab could answer.
I could put my two bobs worth in like Marketing Ploy but it is what is is.
I`m not too shore who pulls the strings there but had `i` been in the chamber of command the headphone socket outlets
would have been stock 1/4`` stereo standard Gold Plated.

: A few tips if anyone is foolish enough to attempt the change over unit to coil plug connection be prepared for failure.
1. if you have fingers the size of Shrek or King Kong or suffer drinker trembles don`t attempt it.
2. the GPX 5 pin round plug OD is wider and shorter than the sdc plug.
The Hole needs tobe widened, extremely dangerous pushing a drill bit towards the circuit board.
i had to recess / rebate the whole a few mm deeper on the outer side of the unit to extend the thread for the retaining nut
attached from the inner side & don`t forget to feed the cables through the nut prior soldering.Heat shrink shields too.
Use a slight amount of silicone to hold the heat shrink in place as heating the stuff is Hazardous around circuit ribbons & wires.
3. When soldering the cables i folded the contact ribbons back with croc clips and used steel wool packed around here & there as a heat shield.
4. When soldering is complete wash wipe the area with water or metho to remove excess flux. It causes oxidization if left on.
5. The plug connections this is where it gets tricky you will have to check & re-check yourself using a test light & low volt battery 1.5 V was my choice.
The GPX plug and sdc plugs are different in configuration. The way i managed it was to connect the 2 plugs together testing in / out on both ends.
``~BUT~`` i `` had the adapter plug cable sdc to gpx already established tobe able to do it.
Write it down do the process a few times check -re--check until your convinced .
Also check the other terminals for bridging in the process.
It`s a difficult one to work out and did my head in a few times.

Red stands alone but is bridged to a disregarded green wire on the back of ( The Original Plug ) i`m not shore what that`s about it is
snipped off just down into the resign seal.
My guess Minelab have used a plug suited for another device probably abundant in their stock . On the sdc 2300 it`s not needed.
Looking from the back of the New GPX plug from the notch anti clock-wise around.
Colour Coding from Unit.
Red =-No1.
Black / yellow bridged.= No2, ( 3 or 4 ) maybe.
Blue = Earthed to retaining nut.
What does my head in here is on the GPX coil cable connections `i` believe No1 & No5 are bridged together.
If anyone with ideas about this feel free to comment.

~That`s it Folks ~ Happy Hunting ~ I`m Shore Their`ll Be a Few Pickers. ~
Stay Tuned for Phase 4 . The Headphone Socket Change-Over`
Agenda 21.
Nice Initiation - Grub Stake

 

[Bush]

Only Fools Jump In.
A few pics of a potential place to mount a headphone socket.
`i` was going to Remove the Original Outlet and replace with a single 1/4`` outlet ( maybe or may not.)
Not that found of removing circuit boards and ribbons as a rule.
Did so prior to check things out ``but``
So this may work an Old Telecom Phone Line Connector Cover as the access point.

Looking at the handbook specs (page 14 P) there is no indication whether the standard headphones Koss UR30 are mono or stereo.
I`m presuming Mono.
My question is does the SDC2300 put out a Stereo output ?
If not then rather than splicing into the headphone plug outlet wires or removing the plug completely.
I may as well splice into the speaker wires which saves me removing circuit boards ect.
The plug i have for the install is one that basically returns the power back to the speaker when the head phone plug is removed.
Similar to the standard outlet plug just if that plug is Mono then i may have to bridge some terminals.

1.So Techno Support is the SDC2300 a Mono Headphone System ?
2.Also could the original headphone socket if left remained be used for anything else besides the original headphones ?
Support here would be appreciated.
I found this post but i`m still not entirely shore.
https://www.prospectingaustralia.com/forum/viewtopic.php?pid=442376#p442376

 

[woomera]

I connected the red + black wires to the headphones and sealed of the other 4 wires, and also disconnected the external speaker for for a boost in volume, I sometimes use a amplified speaker on my shoulder.
This is from Moneybox's excellent post
https://www.prospectingaustralia.com/forum/viewtopic.php?id=28366

 

[Bush]

I connected the red + black wires to the headphones and sealed of the other 4 wires, and also disconnected the external speaker for for a boost in volume, I sometimes use a amplified speaker on my shoulder.
This is from Moneybox's excellent post
https://www.prospectingaustralia.com/forum/viewtopic.php?id=28366

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`I` Knew it was Coming.
01 April 2016 07:14 am
My thought on the head phone socket to a single pin at the unit was to eliminate or minimize a second to third to fourth connections,
that one would have using the adapter lead. From my experience with terminals they all at some time oxidize and can be troublesome.
I`m also wondering upon this is how or what makes the units speaker cut out when the head phones are inserted.
Phasetec obviously has worked that out so potentially it could be done.
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'Talented Old **** isn`t He.
Did read it a couple of times didn`t see anything whether The Machine is Stereo.
When i peeked into it a long time ago there were quit some cables which lead me to ponder if it was Stereo.
If it isn`t then i can`t see why it shouldn`t have been i guess that`s too much to ask $$$$.
Again could the original outlet socket be used for something else like a booster ect if i proceed as planned.

 

[woomera]

I connected the red + black wires to the headphones and sealed of the other 4 wires, and also disconnected the external speaker for for a boost in volume, I sometimes use a amplified speaker on my shoulder.
This is from Moneybox's excellent post
https://www.prospectingaustralia.com/forum/viewtopic.php?id=28366

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
`I` Knew it was Coming.
01 April 2016 07:14 am
My thought on the head phone socket to a single pin at the unit was to eliminate or minimize a second to third to fourth connections,
that one would have using the adapter lead. From my experience with terminals they all at some time oxidize and can be troublesome.
I`m also wondering upon this is how or what makes the units speaker cut out when the head phones are inserted.
Phasetec obviously has worked that out so potentially it could be done.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

'Talented Old **** isn`t He.
Did read it a couple of times didn`t see anything whether The Machine is Stereo.
When i peeked into it a long time ago there were quit some cables which lead me to ponder if it was Stereo.
If it isn`t then i can`t see why it shouldn`t have been i guess that`s too much to ask $$$$.
Again could the original outlet socket be used for something else like a booster ect if i proceed as planned.

I'm no electronic wizard, I try to fix things when it's buggered. I removed the headphone socket on the SDC without taking out the circuit boards. The green + white wires are jumperd together when plugged in and disconnects the external speaker, Moneybox mentioned a boost in volume in his modification, with headphones plugged in and external speaker switched on. I have Steelphase 300 ohm headphones

 

[Bush]

Thanks Woomera,
It`s a bit of a Curly one lets hope Groucho doesn`t come to the party.
The volume increase on Moneybox`s unit is probably due to the ohms decrease or higher conductivity with the larger 1/4`` plug.
More interesting is volume increase with both features on ? i`m no technician here either `i` just splice and dice.
Interesting again also 300 ohm Steel Phase headphones as the Boss UR30`s are 100 ohms i believe.
Do they have volume control on each side ?
I was heading for Black Widow ones but their not cheep.
Not a bad idea either i guess if you can flick a switch from phones to speaker or both certainly be good when your digging and seeking out your nuggets.
Pulling out the headphone plug is only going to wear out the protective coatings.
Pain in the *** sometimes having that lead connected to your head.
Seems like there is a few options available 1 , 2 or All 3. :beer:

 

[Bush]

Alternative cheap coil option for SDC2300.
Compliments to Auman for placing me in the right direction.
The coil seems to operate as well as the standard 8``.
A little tricky die grinding the bracket supports for fitting the detector shaft.
`i` used a rotary chainsaw sharpener to thin out the walls and will build out the outer sides with glued plastic washers to re-enforce the bracket.
Pic of the F158 coil.

 

[EVIE/BEE]

A good reason not to buy second hand stuff.

 

[PeterInSa]

EB, Bush went to (Ipswich where i purchased a GPX4500 for $2100 with lots of extras & which is working just fine.)

To me thats a good buy, the modded 2300, well I certainly would not take that on.