Aquasound

[dbanner]

I'm a bit rusty on the matter.
But I think I recall it being a concentric type coil, but who knows. The Nautilus dmc2 uses a concentric type with identical tx/rx circuit and feedback pots.

If you notice the schematic for the aquasound, the coil is depicted with 40-10-ct-10-40.

Those 10-10 windings I suspect are the feedback coils, which null the RX in a concentric coplanar type coil.(yes, with a centre tap tx, the buck is also centre tap)

So a DD coil only requires 50-ct-50.
The pot connections taken from either side of the coil ends.
This is my thinking.

[Altair]

Next step is to get to work on the coil design. The original is concentric coplanar type, I'm not certain. But a DD coil could be a trickier matter with those feedback pots. Best to try to replicate the original coil first, later on experiments can be made with other coil arrangements.

dbanner,
if original coil is concentric coplanar type, a nulling will be needed, I suppose, like a normal coil for IB detector. Do you plan to use this approach?

[dbanner]

Next step is to get to work on the coil design. The original is concentric coplanar type, I'm not certain. But a DD coil could be a trickier matter with those feedback pots. Best to try to replicate the original coil first, later on experiments can be made with other coil arrangements.

[dbanner]

Here is the layout. Please you can look over for any mistakes. But I think it's good.

One very interesting thing I noticed was that this particular unit has an additional 78L15 regulator which can be switched in instead of the the 78L12, maybe it is used when bat voltage is good, when battery voltage drops, you switch over to 78L12. Or maybe it's normal/boost functionality. I'm not sure, but that's how it's wired. Perhaps the user manual can clear thing up.

I'll update a new schematic.

[Altair]

Guys,
on Ebay there is a sell unit; pcb is dated 2012; pheraps it have a more updated schematic.

[jasonNZ]

I've completed the PCB layout and labeled all the components values etc.

The PCB from the photo provided matches almost perfectly with the known schematic.

There are some observations I made while tracing the layout.

1 The LM358 opamps are switched around, therefore opamp A and B are switched between the PCB layout and the schematic.

2 There is a 100k resistor between pin5 of 393 chip and ground. This is not shown on the schematic.

3 There is a 10nF cap on either side of jfet source and drain connected to ground. Only one is shown on the schematic.

4 There are a few additional resistor's and a transistor and a tl431 voltage reference (tlc431 is left unpopulated on the PCB), associated with the audio section that is not on the schematic.

Otherwise everything looks good.

I'll be posting the completed layout file soon. I need to transfer file from desktop to phone in order to upload. WiFi card is busted.

Great work !!!

[dbanner]

I've completed the PCB layout and labeled all the components values etc.

The PCB from the photo provided matches almost perfectly with the known schematic.

There are some observations I made while tracing the layout.

1 The LM358 opamps are switched around, therefore opamp A and B are switched between the PCB layout and the schematic.

2 There is a 100k resistor between pin5 of 393 chip and ground. This is not shown on the schematic.

3 There is a 10nF cap on either side of jfet source and drain connected to ground. Only one is shown on the schematic.

4 There are a few additional resistor's and a transistor and a tl431 voltage reference (tlc431 is left unpopulated on the PCB), associated with the audio section that is not on the schematic.

Otherwise everything looks good.

I'll be posting the completed layout file soon. I need to transfer file from desktop to phone in order to upload. WiFi card is busted.

[dbanner]

Yes, you are correct. I'll do it exactly as the original.

I have finished tracing out of the layout. Only remains to assign component values and ID.
They need to correspond with the schematic.

[kt315]

sorry, not. preamp has to be in a coil. we need decrease a noise and get 'minelab's wow! 2 inch depth plus' effect.
Main Ratio is "USEFUL SIGNAl VALUE"/"NOISE VALUE". with the peamp in coil we get minimal NOISE value
ie maximal USEFUL SIGNAL. noise is always a cable, cable is additional EMI PARASITIC NOISE Receiver.
look on DEUS - no cable, preamp in a coil, all mind control in a coil, plus PROCESSED SIGNAL TRANSMITTER in a block.

[dbanner]

I don't like the number of wires going to the coil.

I prefer to move the preamp to the box on a small board if possible, thereby making it possible to use standard cable and connector.

Building a suitable coil is going to be interesting.

[dbanner]

DB
JNZ promised me to give full pocket of files. pls wait.

pleasure

The photos of the PCB are good enough to begin working on the reverse engineering.

If there are more pics to come, then all the better.
I have enough to begin the process.

[kt315]

DB
JNZ promised me to give full pocket of files. pls wait.

pleasure

[dbanner]

i cant remember where i got these images from but they have been on my onedrive for a few years now

[ATTACH]50061[/ATTACH]
[ATTACH]50062[/ATTACH]

Thanks for those. I'll trace the PCB and compare it to the known schematic. Now we might have a viable project.

[kt315]

thank you JNZ. read pls my small opus before to do the pics.

https://www.geotech1.com/forums/showthread.php?23641-how-to-do-nice-pics-and-where-share-out

[jasonNZ]

i cant remember where i got these images from but they have been on my onedrive for a few years now