Surf PI Pro

[6666]

Found a picture of pcb, this mysterious 12 ohm resistor is in audio cct
make sure you match the legs of mpsa13 b=b c=c e=e

[6666]

helppp now I have 5v on pin 6. replaced and still the same.

What does this mean ?

[diplodus]

today i corrected BC517's pins position, and soldered potentiometers using wires and 1K trimmer for damping the coil, then i used a phone battery charger to power it up, i got about 8.6v and everything was good, i took some voltage readings with my multimeter and i found that L78L05 gives 6.22v at the output instead of 5v, i don't know if that is going to work, then i plugged in icl7660 and didnt smoke, all other IC sockets get ±6.22
so now the problem is L78L05 giving more than 5v! is that ok or i must have 5v not more nor less?
also i think i will have to use a max supply voltage of 10v because the website says its 12v : icl7660cpaz whereas -according to the datasheet- the max voltage of ICL7660CPAZ is 10v.
for the TLC555 i am still waiting
PS: i noticed that 6.22 is almost equal to RMC value of 8.6v sine wave ( any relation or i am just hallucinating ? its 3 am over here )

[gojo1]

I have 5v on the 5534 pin 6. I have since replaced all chips, transistors and diodes, none of which helped. I pulled the trims out to test but they appeared ok. so any help will be great.

[thebug]

i search the best version of surf pi pro(the sprint layout).


Thank and sorry for my poor english

[rrobsonn]

yesterday i soldered components on the board (except tlc555 and R6), but i noticed that the BC517 transistor must go the other way round to match the schematic so it would be great if anyone could confirm that because paku did the same error with his board, unless he used a different transistor with different pinout (MPSA13).
this is the board if anyone can help (please check also the IC's if they are correctly positioned ):





another thing, i used 4x12 ohm 1/4 W resistors to get 12 ohm 1 W, its a little bit ugly but i hope it will get the job done.
another question, can i use a phone battery charger with about 8 v in the output just to see if the board is working when finished? i used that for the BFO MD and it worked.
sorry for my English, i am not a native speaker

Hi. This PCB are OK?

[rrobsonn]

WHAT IS THE PURPOSE OF D1 AND D2 ON THIS CIRCUIT. From what I gather, NOT HAVE ANY FUNCTION, BECAUSE ARE CONNECTED IN THE SAME TRACK AND ONE WILL AND OTHER COME.

[jladre]

WHAT IS THE PURPOSE OF D1 AND D2 ON THIS CIRCUIT. From what I gather, NOT HAVE ANY FUNCTION, BECAUSE ARE CONNECTED IN THE SAME TRACK AND ONE WILL AND OTHER COME.

In my opinion it isvjust to regulate the current.

[jladre]

Hi. This PCB are OK?

Are you sure you are getting 12 ohms 2watt on your combination?? Im confuse on that!

[diplodus]

hi,
the board is now complete and i am getting sound that i can control with volume, sensitivity and tresh pot but delay has no effect( replaced with a 100K pot but no result ), the sensitivity for small metallic objects is bad only 2 cm or less, for bigger objects (12cm diameter iron disc) i am getting 20 cm, all this ONLY when i am touching the ground wire of the coil with my finger!!! (how to solve that problem?)
the coil is like the one in this website with a 340 ohm damping resistor, the sensitivity and volume at the max, the tresh is set to get a discrete sound.
for now i am happy to know its working but i hope it will get better (at lest better than the BFO i made) by:
- getting a 12v power supply (only 8v now)
-finding the best damping resistor value (and i don't know how so i will experiment with values from 300 ohm to 800 ohm)
-adjusting the delay pot and the small white trimmer on board (marked as delay on the PCB)
-adjusting the trimmer next to TLC555 (how?and what does it do?)
-adding few more turns to the coil
to people who made it before me please help
jladre:for the combination, its 12 ohm (2x12 in series = 24 ohm in parallel with another 2 in series = 12 ohm (24/2) )
thank you very much

[homefire]

The circuit is proven and has been built by many. Ya did a boo boo some place. Go over it again. Did you correct the R18 R22 thing ? My bet is the coil is the issue.


Circuit Requires 12V. Follow Directions Son.......Directions !!!!!!!!!!!

[diplodus]

thank you homefire for your reply, but what's the thing about R18 and R22?
i am using
R18: 47K OHM 1/4W 5% Carbon Film Resistor
R22: 220K OHM 1/4W 5% Carbon Film Resistor
that's what i found in the schematic and pcb, and like i said i will use 12v to power the board, for the coil i think i will have to add more turns to get about 300uH (now i am using 25cm, 30 turns calculated to be about 250uH )

.

[ionut_mtb]

question: i need to find a water pipe in soil, maybe 1meter down. i need to "discriminate" all small garbage from soil(coins, pulltab, beercap, nails...etc) The only coil i have(and the best i made for coins-1eur 30-35cm in airtest) spiral coil 13ID 25OD single speaker cable. Delay pot is 100k. if set for less sens is still pickup nails and some alumin.(no more pickup foil, some low conductive coins..) What to do. Make bigger coil(50cm or bigger) or increase delay pot(more than 100k) ?

[Qiaozhi]

question: i need to find a water pipe in soil, maybe 1meter down. i need to "discriminate" all small garbage from soil(coins, pulltab, beercap, nails...etc) The only coil i have(and the best i made for coins-1eur 30-35cm in airtest) spiral coil 13ID 25OD single speaker cable. Delay pot is 100k. if set for less sens is still pickup nails and some alumin.(no more pickup foil, some low conductive coins..) What to do. Make bigger coil(50cm or bigger) or increase delay pot(more than 100k) ?

Increase the sample delay to eliminate foil, pulltabs and small nails. It should then be easy to tell whether you have a single target or a long thin one such as a metal pipe.

[eclipse]

Correct me if I'm wrong but isn't Delay pot here adjusting width of the pulse (not the delay itself) and so it's usage is quite limited.