surf pi 1.2 problem

[kasperfish]

r11 and r23 in my photo is not 22K resistors?it is wrong resistors?i find this resistors inside bag kit.
r22 in silverdog partslist write 100K. http://www.silverdog.co.uk/shop/imag.../partslist.txt

hi kalaka,

no it are the correct resistors. I made a mistake. I received other 22K resistors with different color code.

[kalaka]

friends the problem solved!!i stuck again all parts and now work!!!

[pat4road]

Hi Silver Dollar. They are correct but are not needed. Silverdog has a lan between these two points on the PCB. Since the color of the whole PCB is the same the lan is hard to see but they are there. I also read in another post in this forum that those two jumpers are not needed.

[kalaka]

hello to all.
surf pi 1.2 now is ok and work very good but i have a question.
if i put the surf pi in the sea (2meter) they want other settings?if yes,what pot want setting?

sorry for my english

[Nezocas]

Hi,
My surf 1.2 as the same behaviour.... good detection on the table....but as soon as it touches the salt water.... I cant detect anything

[kalaka]

you try different settings?

[porkluvr]

Sea water is highly conductive and acts as a metallic target, one that you want to ignore. Tune it out by increasing primary delay.

Also, using a coil with higher than prescribed inductance will cause the flyback signal to take longer time to settle. You could miss short tc targets and/or get false returns if primary delay is set too low.

[kalaka]

primary dealay is P3 on the surf pi pcb?this P3 pot i turned all the way clockwise and is good for gold metal.for salt water i turned left?

my coil now is 20cm 19turns 0.45mm wire (0.238mH).how mH need for salt water?

[porkluvr]

Yes, P3 is delay on Silverdog PCB. 238uH should work well enough BUT that is not the whole story. Cable capacitance, also interwinding capacitance within the coil, all work to slow the signal and that is bad for detecting gold. Using enameled wire instead of using PVC or Teflon insulated wire is not a good idea because enamel insulation is generally thinner as compared to the others, meaning that turns of wires will lie closer together (causing more capacitance that you do not want).

When you choose wire insulation, a higher voltage ratings equals thicker insulation, so best choose something like 600V rated wire instead of 250V. Use the shortest length of connecting cable that is possible. Use low capacitance cable. That has been discussed many times in these forums, I hope you can find the information because I do not have time or energy to repeat that stuff.

I don't have Surf PI but I assume that it is normally for P3 would be wired so that CCW (counter-clockwise) is shortest delay and CW is longest. If you must turn P3 CW to detect gold, I think maybe P3 is wired backwards because gold should be detected with the shortest delay selected. (?)

If your P3 is NOT wired backwards and you must turn all the way CW to detect gold, then you should look towards improving the coil so that you can utilize the full range of delay available!
____________________________________
Look at the bottom of this page for information on building a fast coil, but I'll tell you this - before you go and purchase any type of cable, remember that you must also find a connector to fit it! I have read that twisted pair Teflon wire can make a good lead wire and I intend to try that out in the future (simple!).

[kalaka]

porkluvr thank you for your help
if i turn P3 counter-clockwise not detect gold.(bad coil?)
i will read this page for correctly wire coil but if you have some photo of good wire you help me very much.(i transalate the pages and the translate is wrong many times)

[geoscash1]

Hey kalaka, thanks for the useful info in this thread. Not trying to hijack your thread but I thought this was pertinent.

I have had similar issues with the pulse delay and wondered which was shortest and longest settings, thanks to porkluvr with his reply now I know for sure which direction is shortest (counterclockwise).

my issues are that trying to use any setting other than 100% counterclockwise, I get nothing, no detection whatsoever, down to less than 1 inch with a very very slow response and weaker signal if any.


What I'd like to know is how should the pulse delay actually be working, should it work full range or basically discriminate everything beyond 20% on the dial (moving clockwise) ?

Attached an image so you can see my setting, anything other than where it is set (100% counterclockwise) it is basically useless for anything including metal/iron.

Is there a fix or something I can change to make it more useful....?

Thanks for all the great advice here..

[porkluvr]

Have you ascertained that P3 is wired correctly?? CCW is less delay and CW is more delay??

edit: that statement was directed a kalaka and was made before I read geoscash1's post

IF you have no oscilloscope then you should carefully make sure that you have wired the pot correctly. I will not and can not hold your hand through that process. Naw, wait a minute.... IF you post pictures showing P3's wiring from the PCB somebody could probably figure it out.

Seriously, correct wiring of P3 needs to be a known fact if you are to diagnose this problem. Guesswork is not good enough.

[geoscash1]

Porkluvr, I'll have to assume you are replying to me, I went by what you mentioned in the previous page,

Quote: "I don't have Surf PI but I assume that it is normally for P3 would be wired so that clockwise) is shortest delay and CW is longest. If you must turn P3 CW to detect gold, I think maybe P3 is wired backwards because gold should be detected with the shortest delay selected"

My delay is wired correctly from what I see here in the forum, attached an image, pretty straight forward, but I can switch the wires and see what happens...

Thanks for the reply..

EDIT - porkluvr was replying to kalaka.. sorry guys.

[porkluvr]

Porkluvr, I'll have to assume you are replying to me, I went by what you mentioned in the previous page,

Quote: "I don't have Surf PI but I assume that it is normally for P3 would be wired so that clockwise) is shortest delay and CW is longest. If you must turn P3 CW to detect gold, I think maybe P3 is wired backwards because gold should be detected with the shortest delay selected"

My delay is wired correctly from what I see here in the forum, attached an image, pretty straight forward, but I can switch the wires and see what happens...

Thanks for the reply..

I see where kalaka (and you too) already posted some pictures. I'll have a look (but for crying out loud I am not paid enough for this aggravation.) ha ha

[geoscash1]

Sorry man for the frustration, I am frustrated too with a couple things on this particular board but at least it works when fully counter clockwise.... I just switched the wires and it made no difference
which way they were attached.. only 2 wires for delay on sm pro J Owens pcb..

I Apologise for jumpin in on kalaka's thread...