Can I improve sensitivity on a Whites PI3000 ?

[Anonymous]

Hello!
I own a Whites PI3000 (the yellow one) that I'm succesfully using for beach/shore detecting.
Since I never found coins or rings deeper than a couple of inches, I'm asking myself if I can improve depth of detection by some sort of modification to its electronics.
I already replaced standard alkaline batteries (six) with a self built NiCD pack of 8 AA batteries.
I have the original Whites schematics (don't ask how I got them!) that report a possible Vin of 6.5 to 10.5 Volts at a current drain of 60 to 110 mA.
A NiCD pack of 8 AA 1,2V 800mA batteries can supply 9,6V for about 8 hours with a peak of 10.5 Volts (!) just after recharging.
I did not use NiMh batteries because I believe that power supply must be as much steady as possible expecially when a voltage regulator IS NOT employed in the electronics as is the case of my PI3000 and NiCds have the stadiest voltage supply of all.
It also appears to me that transmission power is fed to the coil directly from V+ that is derived from Vin minus 0.55 Volts circa. So my conclusion is that the higher the Voltage the higher the transmission power injected into the coil. Am I wrong?
Are there other mods to be made to the PI3000?
On the motherboard there is a variable resistor R46 100Kohm that looks to be able to trim gain of the first stage 5534 RX OpAmp. Is this a sensitivity control and what appens if I tweak it?
Happy Hunting
Luca

 

[Anonymous]

I cant tell you how to make PI-1000,more sensitive.Like to ask if its a non-motion detector.does it have 555 IC. How maney.I have white 1000 it has a 5534-IC. IT Amp signal from coil.

 

[Anonymous]

Being a newcomer to PI technology, it still seems as though you might be swinging the coil too quickly or perhaps, adjusting the sensitivity improperly: in Auto or too high (article below mentions retuning regularly as being necessary and Auto retuning reducing depth substantially)--which will actually reduce detection depth, since you won't be able to hear deeper signals-- Lastly, it is possible that there is something wrong with the coil or the detector itself.
Below is a link to an article about the White's PI 3000, which seems to have some good user tips.

 

[Anonymous]

out of curiousity, have you tried test objects to see if it will detect deeper? maybe you just haven't found anything deeper, how is threshold set? no hum, minimum hum or louder? you might be missing signals.

 

[Anonymous]

Whell,'I'll air-test the unit and post results here. I'm using it correctly but I have no references on how deep it should go. One thing I noticed for sure is that it misses some gold, like small chains for example.
I was asking myself if someone made any modification or has someone tested it against other newer detectors.
I read tests of other brands were is claimed a detection depth of 20" on good size coins; that appears to me rocket science.
I can reach those depths only on very big targets like coke cans.
Thanbks all for the help....

 

[Anonymous]

I'll air test the unit and post results.
Thresholds is slight hum, steady and retuned each time it shifts. I'm not a novice. It's just that I can't , at present, have the chance to test a different brand/model so I'm tring to figure out if mine is working and how deeper I can go with newer units.
Just for information we go got at least 100$ in euro coins + une nice gold ring in a total 10 hours of beach search. So it finds something...
I just want it more sensitive to gold and as deep as possible. Digging in the sand is, after all, very easy...
Happy Christmas