Help with Garrett ADS Deepseeker Upgrades

[IBGold]

Hi all, I have an oldtimer mate that still detects with his old Garrett ADS Deepseeker and always complains he did not get it updated/modified when he could years ago can anyone here help with any info on the modifications for them he has a circuit and I would like to help him.
Regards, Ian.

[mikebg]

We need the circuit diagram

Hi Ian,
I am a spokesman for the REMI group, which experts are able to improve any old MD machine. For this purpose, you should send me via email the circuit diagram of ADS and information with the instruments you are available to perform the reconstruction (oscilloscope, function or tone generator). I have a circuit of ADS traced by Wiliam Lahr, but I do not know whether it matches your machine.
The REMI group is training for amateur MD designers, so it has undertaken to rediscover, reinvent, revise and redesign EMI sensor and MD connected to it.
REMI group was founded by amateur radio designers, not familiar with strange English terminology in the field of metal detectors, so we will have language problems with the description of the modification.
Moreover, afther the modifications, must be made adjustment of discrimination. Perhaps the participants in this forum will help to describe this adjustment.

[mikebg]

Ian, the REMI group proposes you to make the following modifications in Deepseeker:
1. To remove DC magnetization from core of input transformer and to tune it in resonance with the TX frequency. For this purpose need to change the connection of emitter resistor and to replace tank capacitor with a trimmer capacitor.
2. To increase the gain of RF amp until the swing of output signal is near rail-to-rail voltage. The gain should be adjusted by operator (or by very slow AGC) depending on ground signal. When using a potentiometer, should have LED indicator for RF amp overload.
3. To increase the power of the TX supplying TX sector directly from battery voltage. Stabilizer is not needed because TX sector has an amplitude stabilizer.
4. Be used more effectively LOW DROP stabilizer for power supply. Then the machine will operate with only 3 x 9V batteries instead of 6 x 9V.
5. To improve the induction balance of sensing head being fastened upon it a ferrite core.

[IBGold]

Added Circuit Diagram

Hi Mikebg,I have a Duel trace digital storage scope and a single trace scope and a function generator there were a series of modifications for this machine and I was hoping someone here would have them hopefuly the attached is the circuit.
Regards, Ian. ( VK5KIB )

[mikebg]

RF amplifier

Ian, start with this:

[mikebg]

Operating point

Ian, the circuit diagram noted as "original" RF amp is for model ADS III.
There must be some benefit from that, instead of one resistor 470K, using two resistors R2 and R4 with resistance 1M.
You should adjust operating point with triangle signal. Connect a scope to tp1 and see how Q3 cuts the peaks. Adjust R3 to cut eqal peaks as shown.

[IBGold]

Mikebg ,I will get the detector from my friend and give it a go will keep you informed. Regards, Ian.

[mikebg]

Low-drop regulator

Voltage stabilizer
This is the modification of supply voltage stabilizer to act as low-drop regulator. The stabilized voltage is reduced to 14V with a view to using only 2 batteries x9V instead of 4 batteries. Both batteries can be discharged to voltage = 14V + Vcesat (approximately 14.4V). The voltage of diode ZD2 is not important to the operation. You can use a LED connected as shown, but it requires other values of R4 and R5.

[mesy64]

please give info about coils.tr and rx????????
number wire and turn and....
best wish

[mikebg]

Tongenerator

Duty Cycle of Tongenerator
Audio in Garrett ADS gives too much loudness (volume) even when used with exhausted to 5V batteries. This modification aims to reduce the loudness without compromising energy efficiency. As shown, be amended duty cycle of tongenerator. The value of RM1 should be adjusted powering audio section with 5V (very exhausted 9V battery). After modification of voltage stabilizer to act as low-drop regulator, machine can work with 2 batteries in series to power the radio section and 2 batteries connected in parallel to power the audio section. When the batteries from the radio section are exhausted to 7V each, they are moved to supply the audio section, where they are exhausted to 5V.

[mikebg]

please give info about coils.tr and rx????????
number wire and turn and....
best wish

Mesy,
In this thread are described modifications, those which use original coils of Garrett unchanged. Indeed coils for these models are not designed properly and can make significant improvements in their parameters, but your goals are needed other coils and other circuit diagrams. Now there was no MD producer using input transformer for RX coil and so resistive TX coil.
In preparing your future coils will be used wire with nominal diameter less than 0.25mm. For TX coil will be used at least 10 reels of wire. You can buy a big spool of wire that has a nominal diameter in the range of 0.12 to 0.24mm. Prepare and 10 empty drums, which will spread this wire, but not hurry to do this because it is not calculated required length of wire in each drum. Soon we will post the drawings of instruments for coil winding.

[Melbeta]

Mike, do you have any modifications for others?

Mike,
I have a Teknetics Mark1, Bounty Hunter Big Bud Pro SE detector, Compass X100, Compass Coin Magnum II, Compass 77b, Compass 71b, AH Pro model Pro-2, Compass Judge I, and Compass 94b.

Unfortunately I do not have any schematics for any of these units.

I would like to enhance any of these to work better, if possible. Thanks...

[Geo]

Mike,
I have a Teknetics Mark1, Bounty Hunter Big Bud Pro SE detector, Compass X100, Compass Coin Magnum II, Compass 77b, Compass 71b, AH Pro model Pro-2, Compass Judge I, and Compass 94b.

Unfortunately I do not have any schematics for any of these units.

I would like to enhance any of these to work better, if possible. Thanks...

Hi.
Take the schematic of Compass 77B

[Melbeta]

Thanks Geo....

Thanks Geo, appreciate it.

[lucifer]

mikebg,
Can you explain the benefit of using such a transformer on the Rx coil? I've seen that only in some Garrett schematics and patents from the 70s. I suppose it is a kind of magnetic amplifier (for example 1:15 turns ratio between primary and secondary coils of transformer) but does it improve performance? And why most of the manufacturers avoid using a transformer?

Mesy,
In this thread are described modifications, those which use original coils of Garrett unchanged. Indeed coils for these models are not designed properly and can make significant improvements in their parameters, but your goals are needed other coils and other circuit diagrams. Now there was no MD producer using input transformer for RX coil and so resistive TX coil.
In preparing your future coils will be used wire with nominal diameter less than 0.25mm. For TX coil will be used at least 10 reels of wire. You can buy a big spool of wire that has a nominal diameter in the range of 0.12 to 0.24mm. Prepare and 10 empty drums, which will spread this wire, but not hurry to do this because it is not calculated required length of wire in each drum. Soon we will post the drawings of instruments for coil winding.