Surf PI Pro

[sdesic]

Problem solved ... got my soldering iron and went over each solder point ...
must be cold joint ... but I don't get it why I did get normal operation ...

OK, now, must do some fine tuning in quiet room ...

have another board to do ...

[sdesic]

Again when I replace delay pot with 100K I get "normal" working detector
but with no sensitivity to gold, silver, copper...

[sdesic]

Changed IC's one by one ...
Changed 2N3906...
Replaced cables to pots, and replaced delay and tresh pots

Now I have some detection ... standard pots (10k, 10k, 1k and 100k) and parts
I found that I have no detection from silent mode
(tresh turned to max) (only strong magnet is detected)

and on some sound on speaker I get faint signal... not one I am used to from surfXX
390R is getting hot ... it is probably that my new 390 resistor is ... 1W

power consumption is 45mA to 50mA with metal close to coil

changing IRF would help ?
must dust of my scope too

[kenny444]

If you think you have component problems, change all your IC's one at a time, this will remove any fault, also check all solder connections to pots etc.

[sdesic]

Tried 580R but no differences ... delay pot on max 100K ... detector is working but only few metals are found ...
no gold ... small depth on iron

will try changing few things tomorrow ... 2N maybe ... different 555 ... pots cables ...

[kenny444]

Try a 470 or a 680, but your really need a variable resistor "that will 'NOT' go down to zero" and scope it to see the wave form. I was using 360R on a Surf PI and ended up with a 680R.

[sdesic]

Nothing new with one more 390R added ... dumping resistor 780R

[sdesic]

I am using standard coil 300 mH and 390 Ohm 2 W resistor (new batch)
Don't know if it will help but I will try

[kenny444]

Damping resistor increase the value by 50%, 100% 150% check for difference.

[sdesic]

I finally found some time to finish my etched boards for Surf XX (from ApBerg).
Drilled and placed components ... but got one problem (or more)

I had all components and voltages in place and no detection.
Moved strong magnet over coil and it produced sound.
Tried to adjust offset trimmer but it is OK... NE5534 pin 6 is 0.02 V
also tried to add some power adjusting trimmer R2 ... nothing better... only strong magnet produced a hit

Managed to change delay pot to 50K and it started working better...
finally I replaced it with 100K pot and it is now OK ... 10-15 cm 1 EURO coin ...
BUT I have very low or no detection of gold ... and silver probably ... nickel also ...

gone over all resistor components in delay part ... tresh also ... all original values from surf xx

my coils are working OK on my working surf XX detector ... 240 and 300 mH

another thing ... volume is a bit low on my speaker and piezo ...


Any ideas ?

[flint]

Hi I'm new to the forum.
I just ordered an ensambled board from tacoma59 on ebay.
Is anybody using this board?
Another question, I have some LiPo batterues from RC, is it ok to use them for the MD?
Thanks
great forum

[Boadil]

Hi everyone, this is my first contribution in this great forum

... after I read all the posts in this thread, I decided (cosmetic) modify SurfXX pcb, to adjust pcb for parts that I have. All parts, except the IRF9640 and ICM7555 (tnx Maxim - free samples), are recycled, from my junk box, and pcb made by photo process.

Detector works by first switching on. After adjustments and changes resistors R6 - 270 Ohms, I have quite solid MD, and wait for Friday to go to the Croatian coast to hunt ...

More details will announce when I can set up attachments, some fotos, and PCB in pdf if anyone needs ...
I checked and kept some changes, maybe it is interesting to someone ...

This is Google translate, my English is not so good.
Regards,

Thanks for your input but still seeing the photographs is a bit tricky to identify components and the value of these, would have the kindness to make a pdf with the components and their identification and values or identify and put beside the identification of the component?
sorry for writing, I am using google translator

[Boadil]

Hi Steve,

From the Official Whites schematic posted above.

Regards, Jim.

you can upload the file again?

[paku]

yes add resistor 470r before connect to LED

[gdogg]

nice