Analysis this schematic

[mohandes]

You seem to have forgot the part where I said that the scope must be set on DC coupling or else DC information will be lost.

But, you have totally misunderstood what I wanted to see. You twisted my words, yet again.

HI

all guru thanks but need finall help

I found small matter but very important.

I FINISH MY DETECTOR AND FIND PROBLEM(better say not problem)
when i connect batterys and have 17 - 13 volts i can adjust all.but when it go down the 13v can not adjustment.

i put TP3=0v
TP5=1.5v(i can adjust it by delay and RV9)[it is hard to me for adjust to 0.6or0.8v){i put delay on 50or100mks, ithink 50mks better}
TP4=0v(discrimination)

and it detector coin(diameter=2.2cm)in air at 10cm and but green led is on?/(maybe true)
AND speaker always tic-tic that can be change by tune volum and when find anything the sound stop, is it true?

[Davor]

Georgi or someone with recent experience with tuning this rig will be able to help.

[mohandes]

find why dont have good detection, gurus what is your idea

mr georgi and gurus Hi
today i go collage for adjustment but pin6 ne5534 is very bad.(i first nulling and then adjust pin6 on 0volts)
So i am going to use lf357?if i use that should be change pin5 and 8 together.
or i change resistor that parallel with coil and change it on 330ohm.(now it is 220 ohm)
which is better,guide me please i finish it buet dont know what i do?


EDIT (this is for gerorgi):you put my post in#95 but i should say you that time Tsecond 4538 not work .

[porkluvr]

Why don't you show us the work you have done on your PCB. Show us the front and back of the PCB, up close, but not so close that pictures are out-of-focus.

edit: Oh, and you say that the U4-6 signal is bad? Well, why don't you show us?
No movies, please... in-focus photos good, out-of-focus movies bad.

Show us how you have installed the compensation capacitor.

[kt315]

11 --->>>>> decrease the damper resistor value.

[kt315]

......

[mohandes]

check itmy friend porkluvr.
what do you think about saying mr kt315.?good i put resistor 180ohm (or 150ohm) ?or decrease coil to 300mkH?
i put picture for your request tomorrow becuse i take film

[kt315]

DO NOT LOAD MY PM BY YOUR QUESTIONS. BUY THE BOOK INSIDE THE METAL DETECTOR AND READ! RTFM!

[georgi.g.zhelev]

mohandes ,Very bad installation, very long wires. MAKE short wires, ok? NE 5534 is no OK!!

[inio_01]

Hello "Guru" Mohandes
Good work, advice from me as you will have something soldered, first try to solder to the PCB component and then cut the rest of the elements (wires) near the PCB, to cut, you can use a good quality special side snips or you can use nail clippers (medium size). The controls would be better to use a flexible multistrand wire (also not too long) than wire phone cord, you can save a lot of nerves when moving or when the electronics will be packing into the housing. Regards

[porkluvr]

check itmy friend porkluvr.
what do you think about saying mr kt315.?good i put resistor 180ohm (or 150ohm) ?or decrease coil to 300mkH?
i put picture for your request tomorrow becuse i take film

NO MOVIE. Still pictures only. DC coupling. I will bend on wanting to see U1-3 at the same time... you can leave that off. But AC coupling for what I want to see is wrong wrong wrong.

You need to NULL the U4-6 output and from your hand drawn picture in #213 it is unclear (but it looks wrong).

Maybe your coil and damper resistor should be changed but you must worry about that only AFTER you get U4 compensation and null properly adjusted.

[mohandes]

hi my freinds porkluvr ,davor and ...
sorry me ,becuase these days i have exam and can not measure psg,but i have a question,what dose value of the frequency the coil ?(point of parallel res and coil connecting)
can i make the coil 1m*1m ,450-500mkh, 1.2-3ohm resistor?(by tel cable beter or Copper wire orhttp://www.geotech1.com/forums/showt...Legend-1/page3 number 53)or i say better this : for make the coil which metod is better ?
regards

[Davor]

This is a PI project so self-resonance of the coil is dampened by the damping resistor. You'll find the best value by experiment. The best wire for the coil is litz wire, which means something like loudspeaker wire with many strands, just like in your link, but every strand insulated. Second best is a wire just like in your link, but all strands tinned (white metal).

[mohandes]

I COMEBACK

hi all gurus
now i have digit scope and can measure all time.
ok.
i adjust all oscillograms but can not set pin6 5534.I replace resistors (100ohm,120ohm,150ohm,180ohm,220ohm,330ohm,470ohm) but that wave(in oscillogram) dont make,,why?
who can explain me? i set pin6 5534 on -0.27volt and (nearly 0)and measure that.

please tell me?i use two coils and both of them not ok.
thanks

[mohandes]

hi all
gurus it is very interesting and wonder for me.i set FCY-PPs on 135HZ and next measure pin3 ne555 and pin6 5534 by oscope.
look at the pics.yellow is 555 and blue is 5534.
just tell me why dont creat the correct figure like oscillogram.
HELP PLEASE OR GUIDE ME(attention to the WIDTH in the figures)
regards