Surf Pi Pro Build

[baum7154]

For greatest depth the round 3DSS is the best choice.

regards,

Dan

[Darin]

My first coil was not good and caused me to scratch my head a bit, said to hell with it and wound a spiral coil with some 22 awg 7/32 appliance wire, this coil is a keeper Not sure why my delay was not working before, maybe the first coil was junk. I did have to reverse the wire on the pot to get it increasing in the correct rotation.

I have 110' of 330/46 LITZ wire I'm going to make a new coil with it and see how that works. Just trying to decide on making a 8" round 3DSS or maybe the 4" X 12.5" 3DSS coil.

[cddz]

I have the same board. Got mine assembled. The delay never really work to start with. Worked ok with a cheap coil I had made but not much depth, I blamed the coil for that but it did work on my MPP not great but did work. I set mine in a plastic box then took it out latter and it was dead. Replaced NE5534 and LM358 to get it working then the sound started going in and out resoldered R34 sound is back but detector still needs work I'm learning so its slow going.

My first coil was not good and caused me to scratch my head a bit, said to hell with it and wound a spiral coil with some 22 awg 7/32 appliance wire, this coil is a keeper Not sure why my delay was not working before, maybe the first coil was junk. I did have to reverse the wire on the pot to get it increasing in the correct rotation.

[Darin]

I have the same board. Got mine assembled. The delay never really work to start with. Worked ok with a cheap coil I had made but not much depth, I blamed the coil for that but it did work on my MPP not great but did work. I set mine in a plastic box then took it out latter and it was dead. Replaced NE5534 and LM358 to get it working then the sound started going in and out resoldered R34 sound is back but detector still needs work I'm learning so its slow going.

[cddz]

Okay,
I figured out the high Dampener resistor reason.
I was using http://www.ebay.com/itm/High-Quality...-/281745576948 to shield the coil. With that removed the best value is now 670.
Noob mistake I guess. I plan to use carbon paint to shield the coil once i get my shell.

[cddz]

question

[ATTACH]34918[/ATTACH]

I had the headphone jack polarity wrong, shorted to +B. Removed and tested resistor and it still tested at 12 ohm. It is on my list Audio still sounds good

[kt315]

question

[cddz]

This might seem an obvious (or even stupid) question ... BUT, are you sure it's actually a 4k7 and not a 470R?

It is 4k7, not 470R.
I am not sure what is going on with it, I couldn't get it to ring at all so I took the parallel resistor off the tool.
Going to take another look over the board, I must have done something when I removed it from the enclosure last night.

[junkhunter]

Nice job cddz and i have better success with a lose wound coil .Also can you swim under water with it .there is a challenge

[Teleno]

Replacing MOSFET IRF9640 (200V) by FQP3P50 (500V) can gain you 3 us.

http://nl.mouser.com/ProductDetail/Fairchild-Semiconductor/FQP3P50/?qs=FOlmdCx%252bAA3ubP75ib961Q%3d%3d

[Teleno]

The Surf PI Pro has no current limiting, so the coil current will depend on its inductance.

The timing is as follows:

Ton = 50.5 us
Toff = 1.6 ms
Freq = 615 Hz

If you measure the parasitic capacitance of your coil you can play with the attached LTSpice simulation.

[jladre]

It is impossible that this machine work good with 4k7 resistance, its too high..

[Qiaozhi]

Riddle me this. 4.7k dampener resistor for this. Something must be wrong again . Although the delay setting seems to work now. I can pick up a .5 gram piece of gold at 4.5 inches, is that good?

This might seem an obvious (or even stupid) question ... BUT, are you sure it's actually a 4k7 and not a 470R?

[daverave]

i have found a damping resistor between 390 - 450 ohm is correct for the surf pi.

[cddz]

Riddle me this. 4.7k dampener resistor for this. Something must be wrong again . Although the delay setting seems to work now. I can pick up a .5 gram piece of gold at 4.5 inches, is that good?