TGSL 100x100mm build questions

[yatahaze323]

Hello everyone,

I had my pcb boards from the other thread printed and I've been populating the board with parts. I realized that I need to order some additional parts for this project so I thought it was a good time to stop and ask a few questions.

In the pcb placement from the sticky post I noticed that there are a few things that are not labeled.

A1 - A5 What are the values for these Capacitors?

B1 & B2 Are these pots for Disc and Sensitivity?

C1 - C6 I'm not sure what these are for, I've seen a few pictures of other builds that these connected to pots or switches. What are they used for?



Here is what I've done so far with my build, please point out any mistakes that I've made so far! Thanks for any help I appreciate it!

[Nandor]

Hi
A1-A2=15nF or 4.7nF+10nF
A3=10pF
A4-A5=22nF
B1=Geb
B2=Sens
C2-C5-C3=Disc pot C2 is minimum Disc C3 is Max
C4-C1-C6= Disc Switch C4 Disc mode C6 All Metal Mode

Regards

[yatahaze323]

Thank you Nandor! I appreciate your quick response!

[ne555]

Hi i have questions r13 and r14 = 5k1or4k7? I don't find file lay pleas any one have it

[chevesne]

http://www.geotech1.com/forums/showt...257#post240257

[Nandor]

Yatahaze after you make several units you wil know

Ne555, not so important you can use 4.7k or 5.1k without any noticeable difference!

[ne555]

Thank you for answer me

[Nandor]

No problem
That resistor sets the gain of the filter and the cut off frequency and by changing the value from 4.7 to 5.1 has little effect.
4.7k-4.7uF=7.20Hz
5.1k-4.7uF=6.64Hz
Also those 10uF electric capacitors have a large tolerance rates of 20%. If you meaure them you can see that most of them have less than 10uF, 8.7uF or 9.2uF so using 2 back to back will not give you the nominal 4.7uF.
The most accurate choice would be using 1% 4.7k resistor with 5% 4.7uF polyprop caps and matched in pairs so each filter would have the value.

regards

[Nandor]

Yatahaze pay attention to the transistors pins! I think that you have misplaced the Jfet J107 it's not BF245, it wont work that way!

[yatahaze323]

Thanks again Nandor, I was unaware that the pinouts would be different I'll take a look at them and make the changes.

[ne555]

Just i have 5cm depth for silver coin 10mm size my rx 6.4 mh and tx 5.9mh wair. 25mm whats proplem?

[ne555]

https://youtu.be/YpnEfs3WGo4

[kt315]

delete foil and do test again. you do not need shielding if your coil is stacionar.

[ne555]

Even without shielding does not give the desired depth I think the problem in the components of the board the problem not in shield

[ne555]

Transistor in my board 2n2907a/-331....2N2222A/H331...BC547B/166....BF245C/BB12... Ic is lf353n...lm393p....lm358p..lm308n...cd4024be...all r 1/4w and all c nf to pf 16to 50 v