Whites Surf PI schematic

[porkluvr]

Hello everyone. Its main surf.No sound, may have given some to help me. I looked at all the posts I have found a similar problem anywhere. thankful in advance

In your top photo it looks like you have three 1Ω resistors in series, totaling 3Ω.
IF that is your damping resistor you should have (depending on your coil) about 390Ω there.

[satdaveuk]

Tea

Hello Friends,

Well if we where neigbours it was easy... a cup of coffy and some live to the scope...but as we are from al over the world this in not easy to do...
In the past I made from the Surf some different boards, build them and had no problems so far..but as other components can be used ..
Looking at al the posts about the surf I see that there are some problems here and there..
Also "Joop" had a problem with the sync around the ICL7660 and made a mod as follows ?

So it can be that a modification can help solving the problems some have ?

Look at the drawing...

Replace R3 for a resistor 1k5
Remove link from the +Batt to the 2N2906 and replace this link for a 100 ohm resistor
Remove R17 and the Diode
Drill a small hole in the ground track to place a cap from 220pF that has the other leg in the anode from the removed diode
Replace R5 for a resistor from 100 ohm.

Well I hope I have not made mistake's but... I hope that more off us will check this mod.. (If I had to eat al the mistake's I made in the past... ...)

Best regards.

Ap


[ATTACH]24121[/ATTACH]

Hi ApBerge

I drink Coffey but prefer a nice cup of strong Tea two sugars and a splash of milk .
The likes of you me and others like Simon Baker would be in and out of each others workshops quite regular I think if we were neighbors.
Far as modifications in general they are a good to play around with but only when your project is up and fully running as per original specification .
Ive noticed theres quite a few on here and across the forums doing modifications to projects because they cant get them to work correctly which is not the correct way to go about things and putting it bluntly is nothing more than a bodge job.
If your project is not working correctly on a proven design such as ApBerge lay files then theres a fault or faults that need to be addressed.
First things to check is your construction , if the problem doesn't lay there then look into component spec because it can only be one of them to things.
When constructing as Ive stipulated so many times don't just judge a component by whats on the label always check with relevant testing gear before installation so as to get a nice precision working project.

After that trying mods and experimenting is good practise.

Regards

[dimovnis]

Hello people. These days I have tried to do something but I did not succeed. I found that the BC337 hot. I replaced BC337 with new but still the same. I put the bc639 not heating up there, just one tone, and does nothing more.
Sorry about the poor ENGLISH

[escarabajo]

Hello Dimovnis, if you are replace the 2n3906 for BC337, is a mistake.
The 2N3906 is a PNP transistor and BC337 is NPN, you can replace the 2N3906 for BC556, BC557 or BC558, this transistors are the same type PNP, and the parameters are closer than 2N3906.
Be carefull with the Pins in the "BC" transistors are diferent from 2N3906.

I you see the 2n3906 with the flat side up, the pins are (from left to right) E B C

The "BC" transistors,seeing with the flat side up, the pins are , (from left to right) C B E

I hope this information can help you

Be patient.

Regards

Escarabajo.

[dimovnis]

My surf began to run, but poorly. Reacting only on audio speakers, a second metal is not recognized, iron, silver, gold, aluminum finish does not see ... This is my video please big help.

[Tepco]

This is really unbelievable failure, it reacts only to magnet. Seems that RX part is OK, 555 works, so check two possible issues. Most probably TX power pulse is missing (drive is OK), something around MOSFET, check soldering, PCB, transistor itself etc. Use multimeter to monitor current consumption, with and without coil connected, if it is about same, this is the problem. Also check your coil, just in case two parts made of two different wires may be connected in wrong direction (opposed, instead in series). Not to mention, you will need another coil.

[escarabajo]

Hello Divmovis, when assembling my surf pi circuit, also had trouble adjusting, detected only a very short range.
After an oscilloscope and instructions I found on the forum so fit.
If you have no oscilloscope can do the following:
1. - Put a voltmeter between the center pin and turn delay potentiometer to read 4.80 volts.
Two. - Turn the potentiometer sensitivity or gain to a minimum.
Three. - Turn the potentiometer to the minimum threshold, you will hear a continuous tone.
4.-turn potentiometer sill slowly, until you hear a slight tone, almost audible and leave it.
5.-With potentiometer or gain to the minimum sensitivity tests for detection with different metals and slowly turn it to increase the range of detection.
6. - When you hear the tone becomes unstable, turns a little more threshold potentiometer, to achieve maximum detection range without the threshold to become unstable.


my coil is 23 turns of AWG24 magnet wire , a diameter of 9.5 inches, and 1.3 ohm.

the shape of my coil is not spiral like you coil, is only 23 turns with 9.5 inchs diameter tight with plastic ties.


damping resistor 330 ohm.


Best Regards.

Escarabajo

[paku]

i make long pcb my problem is same like dimovnis

[Jose]

I had problems with the Surf PI, already discuss elsewhere in the forum, but I repeat again, to try and help those in trouble.
The cause was a malfunction of T1, apparently by the type of 555 that I'm using, producing poor bias of this transistor
This transistor (T1), saturated and collector pulses are weak or low amplitude making it run incorrectly the 4093, the pulse delay, appears immediately after the pulse TX, (no delay work), producing MD malfunction.
The best way to check if T1 works well, is with the oscilloscope.
Without oscilloscope, you can measure the voltage between collector T1 and GND, and should be around 3.8 volts.
If the voltage is higher, in my case was 11 volts, then T1 is not working properly.
I solved the failure by installing a 3.3K resistor between emitter and base of T1. Jose

[jlsilicon]

The first page starts by explaining that this design can be used with discrimination (for gold) using the Delay Pot.
Is this true ? - On a later page, discrimination was brushed off as not part of the design.

[Jose]

The first page starts by explaining that this design can be used with discrimination (for gold) using the Delay Pot.
Is this true ? - On a later page, discrimination was brushed off as not part of the design.

Discrimination as such, does not exist, what happens is that when the control delay increases, the detector is less sensitive to aluminum foil, less sensitive to some bottle caps depending on their composition, and gold, while still detected with good signal, bronze coins and iron.
This in a way is some discrimination, that in certain cases it may be useful.
You can increase the delay time as shown on the first page and then experiment with different materials to see what their effects.
José

[liekwang]

Hi all I'm interested in the PCB Board ApBer with a long Board and simple do this Board work what is the path and its components in accordance with PCB layout Board I would like to try to make this Board does really work for anyone in this forum please give me explanation thank you

[inio_01]

Hello
After assembling a long plate detector work properly about 30 seconds, then started to heat up the IRF, which consequently burned along with tlc 555, after investigation the cause was C2 (1000uF) which also heated up , replaced the burned items. I have a question how it should look the signal at the collector of transistor Q1?, on a base is the signal from the 3 pin NE555, the emitter v. 11.8


Regards

[Jose]

Hello
I have a question how it should look the signal at the collector of transistor Q1?,


Regards

Q1 collector waveform, approximately 17 volts.

[inio_01]

Hello everyone


Thank you Jose that's what I needed


Regards