Detection problem

[Carl-NC]

The SMPI design is fine, White's has been selling it for over 25 years. At this point you will likely need an oscope to figure it out.

[Hach]

Hi. I don't know in electronic execus me where is damping resistor that should warm.
This board that I show you I bought it then it's collected by engineer.

[Hach]

"To increase the volume, reduce R34 value at MPSA13 emitter. try 47 or 33 ohm"
How could I do this? Can anyone help?

[kt315]

good to start to learn is ITMD book. this is mine help. and yes, it is jut smart ***** unsarcastic comments.
Carl is right as always. i try to limit my posts to helpful responses but sometimes that is not getting in absent english.

[Andi68]

How about a book to learn English?

[Andi68]

Unfortunately, I can not insert smileys, yes, the whole response function works very bad

[Carl-NC]

Hi. I don't know in electronic execus me where is damping resistor that should warm.
This board that I show you I bought it then it's collected by engineer.

I don't know what schematic goes with this board, but I suspect R6 is the damping resistor. The big one.

"To increase the volume, reduce R34 value at MPSA13 emitter. try 47 or 33 ohm"
How could I do this? Can anyone help?

Unfortunately, if you don't know anything about electronics and don't have the necessary equipment, you're probably stuck. I suggest going back to the guy who built the board for you, see if he can help.

[kt315]

How about a book to learn English?

how about to learn russian? here is Vladimir Poliakov, very famous persona with lecture "Energy production from the electromagnetic field and other natural sources"
or getting the energy from EMF and other natural sources.

https://www.youtube.com/watch?v=uUa_y-E931U

[Hach]

Hach, at first I thought you bought a White's Surfmaster PI Pro on eBay, but I see it's a PCB you then built. When things go right, this is an easy circuit to build. When things go wrong, an oscope is just about necessary to figure it out.

My questions were based on the possibility that the transmitter is either not working, or just barely working. A big piece of iron can produce a response whereas a coin or ring won't. If the transmitter is working, the damping resistor should be warm. Probably the FET, too.

If the transmitter "feels" like it's working, then the next likely culprit is the RX timing. That's where an oscope is essential.




KT, I have to agree, your response was incredibly unhelpful. Maybe try to limit your posts to helpful responses.

Dime, try to ignore posts and people you don't like. Life will be better!

R5 according to the schematic is RX timing when I Touch it with multimeter pin the coil start detect silver ring at 20cm so now I know where is the problem. Thanks alot Carl.
But what is the next Procedure? must I chang the R5 1k5?
Or what?

[Andi68]

kt - that's a good idea - many russians live here

[Hach]

The Ebay seller help me1- R2 must configure correctly 2- recommend to use Litz wire for fast coil 13cm 26turn3- Joint between coax and coil must be soldered 4- coax must be low capacitance I have to confirm "surfmasterpro" Board working Perfect and Not trash layout pcbThanks guys for trying help me.Note for some Speech is silver, silence is golden.

[kt315]

silence is platinum if from the platinum member. you/your ebay seller touch/es very intriguing subject - we call that 'the fastest coil' or 'the basket coil'.
yup, litz and some specific winding way.

[Carl-NC]

1- R2 must configure correctly

R2 sets the frequency and TX width. If it's grossly wrong, it might cause the problems you see. But usually, R2 can tolerate a fair amount of error.

2- recommend to use Litz wire for fast coil 13cm 26turn

This design is not extremely high performance. Litz wire is probably a waste of money. Use magnet wire, or insulated stranded wire. 24awg or larger.

3- Joint between coax and coil must be soldered

Yes.

4- coax must be low capacitance

As best you can, but again this is not a high performance design so any decent coax should work fine.

[Hach]

Carl Thank you very much
Your advice really appreciated.

[waltr]

My coil 13cm with 100turns wire size 0.6 with insulation

Try something like 26 turns. I think 100 turns would cause the first sample to be pegged to one of the power supply rails, this would explain the iron only response with only the second (late) sample working

I agree.
65mm Radius of 100 turns is about 2.8 mH. This detector needs about 300uH coil (Note: m = milli or 10e-3 & u = micro or 10e-6)

There is a good coil calculator at the top of the COIL sub-forum.