Give me a single panel Surfmaster PI (White's) / PCB

[silver]

Hi Barry
Q6 is BC337 and its orientation is 180 degree with 2N3906, so its orientation is true, but at first it was at incorrect orientation so i did chenged it.
thanks for your attantion.
Silver

[silver]

Hi
can i use this shematic for power supply (+5 and -5v), if yes, what is better?

[cristi71]

hello, first scheme does not work. the second works but have batteries

[bernte_one]

have a problem too

today i have finished single sided pcb.
all parts are placed and i get a continuing sound when i connect the power.
turning volume pot makes an effect -get quiter or louder. i have checked other pots too -
right connected but no effect when turning. coil is connected.
i use a 470 ohm pot with 4w instead of 390r resistor (coil damping) turn the pot for testing to 390r only at this pot i can hear a change when i turn it to zero resist but i cant detect something

has anyone heared this continuing sound effect before
at the double sided longbord version i only get a short sound when tunig at right point

[porkluvr]

i use a 470 ohm pot with 4w instead of 390r resistor (coil damping) turn the pot for testing to 390r only at this pot i can hear a change when i turn it to zero resist but i cant detect something

What happens if you remove the pot and install a 390R resistor?
I have heard of people blowing out pots. The 4W rating applies only if the applied voltage is across the entire resistive element, but you turned the knob to "zero". That could apply the entire flyback energy to only a small portion of the resistive element.

If you want to fine tune a damping resistor using a pot, it is less likely to damage the pot if you also have a fixed resistor in series.

[silverdog]

I would Check C7 caps you have used, they look large for pF values

I was building something on a breadboard the other night and by mistake put 220nF instead of 220pF on 7660 OSc pin to gnd - the result approx 0v on pin 5
I changed to 200pF and everything ok !

[bernte_one]

thx silderdog c7 is ok but semms that i hace touch the c4 100nf with my solder iron the palstice is melt at one corner could this such permanent sound



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please no lugh made it wrong sided but that ok

[smity]

Take a toothbrush, soap, alcohol and go to the bathroom to wash the PCB. Such products do not have to work.

[bernte_one]

thx smity that helps me much

[silver]

Hi all
today when i used the second shematic for + , - 5V instead of 7660 power supply, finly it work fine and both ofset and dely work fine and can detect a 1inch brass coin at 15 cm, but it is short distance so any info to increase my detection depth is very helpful for me.
my coil is 21 cm in dia with about 0.290mH.
many thanks
silver

[cristi71]

attention to mpsa13. if use is equivalent Darlington

[mrjangles]

Does anyone know how to do the 25us to 15us mod made my surfscanners detectors for the Surf pi. It is supposed to increase depth and sensitivity to small gold.