Nautilus DMC IIb schematic

[aothunterpl]

Hello, is anyone have a schematic for this interesting old detector?



Regards

[kt315]

here 44MB rar of files... enjoy
coil, board, schematics. http://depositfiles.com/files/6t9f13d5j

on a serve...

[aothunterpl]

Wery thanks again

Regarts

[dfbowers]

Thanks for sharing. I will eventually attempt to build.
Don..

[dfbowers]

There seems to be similarities between the IIB and the Aquasound, specifically the loop balance and TX power adjustment. Anyone ever seen a schematic for the IIB?

[kt315]

yup Don i remember your reply on Aquasound that it is all-metal mode of IIB. Aquasound has specific coil also, i am not able
write in english that rincipe of increasing of voltage in coil. someting like if we will take a fishing rod
and begin to swind so its end will give more amplitude. thats why there is (52V to the coil in high powered mode and 32V in low power).

[yoyo27983]

Hi all,
I have also been searching for schematics for the Nautilus IIB and IIBa. I borrowed a IIBa and took pictures of the boards. As it was a working detector and belonged to a friend I did not attempt to trace down this board as it was a bit of work to get it out of the box and I did not want to risk damaging it. I did testing on the frequency and on the 10" coil. This detector had an automatic GND balance daughter bd that had 6 ICs which had the markings ground off with a dremel tool. There may be a patent on that board. BUT he also had another unit that was the DMC II that he gave me which I did reverse engineer and get a schematic. I also did lots of testing on this boards. If anyone had a Schematic, please share it with me. THe most interesting thing I noticed was that they used a metal bolt to attach the coil to the shaft. I would think this would interfere with the operation or at a minimum tend to affect the magnetic flux pattern and possibly partially dampen the sensitivity. Both the units he had used a metal bolt. They may not have been original though.
If anyone had a Schematic, please share it with me.

[kt315]

THe most interesting thing I noticed was that they used a metal bolt to attach the coil to the shaft.

it's old detector and this was a time all companies used just metal bolt. can you email me pictures of pcb in high resolution?
i must reminder you the coil has preamp inside. on transistors.

[Mario-j23]

Hi,
I also tried building a copy of Nautilus IIB, but it unfortunatly didn't work. Could I also get the pictures of the pcb? Maybe I could find an error somewhere.

[yoyo27983]

Easier for me to put them in my google drive for everything I have on it. I took a lot of pictures and I was collecting as much information as I could find on this machine anywhere I could find it. I find it very strange that this is an award winning machine and there was no more info on it on the web than what I could find.
I will leave these up for a while. I was in the process of writing a paper on the reverse engineering of this and you can read the word document I had started on it but I decided that I would have to keep my friends detector a lot longer than was needed as the repairs I had to make to it was simply replacing the cord on the headphones. I also did not want to risk breaking it. I did take some measurements with my O'scope and voltmeter which are in the notebook and did not get typed into the word doc. I was also disappointed not to be able to read the components on the autotune Bd. These pictures probably won't give you what you want to see as I did not take the main board out of the unit.
I then spent my time on the VLF that he gave me and I did much more testing and dissecting on that machine. I still have it. I do have a schematic that should be correct. I drew it in Micro-cap but not knowing alot about the software, I got tired of trying to get a simulation to run. BTW, my method of circuit tracing was to mark the traces with a sharpie as I drew it out and use an ohm meter A LOT!

https://drive.google.com/drive/folde...Oj?usp=sharing
Also added a folder for the VLF that I did the schematic for including the schematic.
https://drive.google.com/drive/folde...dW?usp=sharing

[kt315]

thank you for pics. also, you have to know/understand the Nautilus coil has a RX preamp inside.
you may load files from my disc. i got the pics from russian guy and his preamp board sketches. https://drive.google.com/file/d/15SR...usp=drive_link

[kt315]

seek a folder Nautilus_DMC in the archive.
then open a folder coil inside. you have to load 5 GB size RAR.

[kt315]

file with schematic DMC_2_sch.pdf
take attention on lined contour with word HEAD. it's the pre amp part inside of the coil.

[yoyo27983]

thank you for pics. also, you have to know/understand the Nautilus coil has a RX preamp inside.
you may load files from my disc. i got the pics from russian guy and his preamp board sketches. https://drive.google.com/file/d/15SR...usp=drive_link

Yes, I did know the 2Ba had a preamp. I suspect (thinking like a tech) that is how the modern multi frequency machines must be getting away with making the coil resonant at different frequencies, by switching different caps in parallel with the coil at the preamp. I would love to know if I am correct or not. I have a Nokta Legend and looked at the frequency output of it in multi modes. It appears to be a variable pulse width modulated square wave. The other Nautilus, at least the VLF that I have does not have a preamp. It appears to be a concentric coil only. (4 wires). I also wanted to Know if Jerry Tyndall was a ham radio operator. Just curious. I don't live too far away from Coats NC and drove to the address where his shop was. Just wanted to see where this legendary machine was made.

I searched for Nautilus_DMC in the search bar and only got a hit on the post you just made. I am not familiar where the Archive is located.

[kt315]

I am not familiar where the Archive is located.

the Archive is on my GOOGLE disc, i give a link above in post.