Nokta velox one coil reverse engineering

[Coilbrain]

You need an LCR meter to measure inductance & capacitance. You can't reasonably do this job without one.
Here is my take on the internals:


Having the cable gland on the RX side is a bit unusual, you normally want it on the TX side to minimize RX pickup of cable flexing. Anyway, the single wire straight up the middle is a ground drain embedded in the shield of the upper housing. There is a second drain wire that is embedded in the shield paint of the lower housing (under the TX winding, you can't see it). These are connected to the RX(-) side, which acts as the shield ground connection all the way to the main box. Likely the 5-pin connector only uses 4 pins.

I agree with the others that the 3-pin device is probably a trim pot. The proper values and pot setting will be difficult to determine. This is where you will need an oscope and maybe a signal generator.

I am unable to determine if there is shielding as far as I know its plastic and resin not sure if there is shielding inside (would the shielding not black or at least show on x-ray)? please explain I'm no expert at all

[Carl-NC]

There is shielding, most likely carbon paint applied inside the housing. Won't show up on an x-ray.
That o-scope is a single channel, you will need a 2-channel. I once bought one of those cheap handheld scopes, it was barely usable. That was 10 yrs ago, maybe they're better now.

[Coilbrain]

There is shielding, most likely carbon paint applied inside the housing. Won't show up on an x-ray.
That o-scope is a single channel, you will need a 2-channel. I once bought one of those cheap handheld scopes, it was barely usable. That was 10 yrs ago, maybe they're better now.

what do you think about aluminum foil wrap shielding or copper shielding if i am unable to procure carbon paint also do you recommend ferrite shielding somewhere on the cabling ?

[Carl-NC]

You could try foil shielding, but I would recommend instead a metallized fabric tape similar to 3M's CN-3190, it's much easier to work with. Carbon paint is easily found, look for MG Chemicals 838AR.

[Coilbrain]

You need an LCR meter to measure inductance & capacitance. You can't reasonably do this job without one.
Here is my take on the internals:


Having the cable gland on the RX side is a bit unusual, you normally want it on the TX side to minimize RX pickup of cable flexing. Anyway, the single wire straight up the middle is a ground drain embedded in the shield of the upper housing. There is a second drain wire that is embedded in the shield paint of the lower housing (under the TX winding, you can't see it). These are connected to the RX(-) side, which acts as the shield ground connection all the way to the main box. Likely the 5-pin connector only uses 4 pins.

I agree with the others that the 3-pin device is probably a trim pot. The proper values and pot setting will be difficult to determine. This is where you will need an oscope and maybe a signal generator.

can you please elaborate on the usage of an oscilloscope and signal generator (should I use a small coil hooked up to the oscilloscope to induce the signals, or splice into the cable or just use the coil directly on the oscilloscope) do you have ideas on how to narrow it down.

[kt315]

all questions' answers are in the copy ITMD. just order it at amazon. understanding will be nice before to ask something.

INSIDE THE METAL DETECTOR.

[Carl-NC]

can you please elaborate on the usage of an oscilloscope and signal generator (should I use a small coil hooked up to the oscilloscope to induce the signals, or splice into the cable or just use the coil directly on the oscilloscope) do you have ideas on how to narrow it down.

I would drive the TX with a sig-gen and characterize the RX response over frequency using the oscope. That might give a hint as to what you need to do in a homebrew coil to match the response.

If you don't have a good understanding of electronics, then this project might not be a good place to start learning. Detector coils are really simplistic, until you start building one.

[Altra]

For reference. Not sure of the accuracy?

[Coilbrain]

For reference. Not sure of the accuracy?

may I ask for references and or where was this procured? Im very intrigued. If there was someone who already mapped it all out he would be a major help

[Altra]

On this forum, search Chirak here. It may have been removed? I saved it the same day. I would like to see the complete schematic also.

[Coilbrain]

On this forum, search Chirak here. It may have been removed? I saved it the same day. I would like to see the complete schematic also.

damn I wish I searched everything on google, google image, here... i wish you could dig up a contact or some lead

[Carl-NC]

Try this thread (found by doing a search on "Velox"):

https://www.geotech1.com/forums/foru...okta-velox-one

Note that Cirak only posted twice, 7 years ago. You can try to PM him.

[Altra]

Another thread with pictures of the pcb post 6 and Tx coil specs post 8

https://www.geotech1.com/forums/foru...0432-velox-one

[Coilbrain]

Try this thread (found by doing a search on "Velox"):

https://www.geotech1.com/forums/foru...okta-velox-one

Note that Cirak only posted twice, 7 years ago. You can try to PM him.

Well thank yo so much for sending me this I was able to track him down i'm waiting for his reply at the moment the guy is a professional in his field it seems.

[Coilbrain]

all questions' answers are in the copy ITMD. just order it at amazon. understanding will be nice before to ask something.

INSIDE THE METAL DETECTOR.

is there a pdf version I can purchase I don't have amazon