If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
That's OK, Zed. You did a great job on tracing out the circuits. Even if it has mistakes (and I'm not saying your schematic does or does not). I would have pulled out the rest of my hair attempting the feat of REing the SD. Your product is 10,000% more than what we had before.
In all reality, somebody who would attempt to copy or borrow on the circuit would probably be able to deduce FET "dash" number from other circuit components. No harm done. So you left off the dash number? Big deal. That's not really a mistake because the normal hacker would think twice before sticking a dash-600 in the transmit circuit, but Investigate more reasonable offerings.
Whose idea was that, -600 anyway? Veltex! No, seriously, mistakes are human - but we don't want to perpetuate them after they're discovered
I just wish we knew if veltex's drawing was made from a fresh tear-down, or more probably, using a previously available RE drawing as a guide? Anyway, thanks to all who made the SD2000 schematic available whether it be from your tear-down or somebody else's. It's all food for thought and good information, even if there are minor errors.
With a product of this complexity a perfectly accurate RE would be highly unlikely.
Hi veltex Thanking for your nice drawing . I had some of your drawing. Best regards.
Hello
Someone here know how to build big concentric coil for SD 2200 D Minelab pulse induction ???. This coil should be big enough to detect big objects and not detect small iron nails.
Someone here know how to build big concentric coil for SD 2200 D Minelab pulse induction ???. This coil should be big enough to detect big objects and not detect small iron nails.
Regards
Hi Morgan This is my opinion : If you increase Pulse induction detectors coil, sensitivity to small Iron object will be reduced .but with this method, we cannot mask iron items completely with pi detector . Another method, is moving and displacement of sample pulse. Although reduced sensitivity to small iron object , probably you Lose gold and silver items. My homebuilt pi detector with 1 m X 1m loop easily detect small pegs of shoes. I did very try to reject it ,Without good response. Constructing of big coil , wouldn’t solve this problem . Use VLF detector , some of those ,reject iron completely. Best regards.
Hi Morgan This is my opinion : If you increase Pulse induction detectors coil, sensitivity to small Iron object will be reduced .but with this method, we cannot mask iron items completely with pi detector . Another method, is moving and displacement of sample pulse. Although reduced sensitivity to small iron object , probably you Lose gold and silver items. My homebuilt pi detector with 1 m X 1m loop easily detect small pegs of shoes. I did very try to reject it ,Without good response. Constructing of big coil , wouldn’t solve this problem . Use VLF detector , some of those ,reject iron completely. Best regards.
Yes,but VLF not penetrate ground like pulse induction detectors...
So,you tell me , with PI coil 1mx1m,you still detect small iron nails,are you sure ?
Yes,but VLF not penetrate ground like pulse induction detectors...
So,you tell me , with PI coil 1mx1m,you still detect small iron nails,are you sure ?
Hi Morgan Yes, my coil was fast type and sample pulse tuned very near to decay point (specially For gold detecting) PI and 1mx1m loop built by myself and my friend help me for test it. He did conveyance 1mx1m loop. And he went into the center of loop , when walking, I heard some signals at headphone periodically!!! Peg of his shoes produced metallic object signal at output. After replace himself shoes with plastic shoes. Problem was solve. Best regards.
privet kt315 pa moemu ti gavari6 pa ruski? ia sdelal plat i ha4u vmestit v etava sait no o4en bal6aia trudnast dlia mine esli ti dau6 tvai adres ia dam shematk plat mojna pablikuvae6 suda ia is bolgari mne zavut dima
Geez thats an old video, lol, The SD2000 is an antique compared to the Schematic of the GP3000 series detector. The GP and GPX use 2 low noise input stages and a separate Earth field cancellation input stage. The secrets are in the low loss low noise input stages and the cleverly designed filters that remove most signal below 5 ot 6 Hertz. The only way to see what is happening in the very small voltages on these detectors is to trick them they have 180 volts on the reservoir capacitor or change the resistor divider on the voltage comparator, then you must load the output stage into a 0.5 ohm resistor. This will still make the detector function and you can then observe low level signals without the induction pulses upsetting the measurements. Novel design improvements are like BF908 dual gate Fets on the opamp inputs to remove noise from the inputs of the AD797 devices, only 5pf cap from a BF908. Then after a small amplification of 47 Times both inputs got to a 4053 and then to a pair of TLE2142 in series. Then its a resistive network thats mainly 10K and 20K resistors and then feeds into a set of 4 X 4053 controlled by a pair of 74HC273 devices, this is then fed to the integrator section and then given a bit more amplification with TLE2072 and then goes into a series of band pass filters.
The Timing of the Mux (273) is controlled by 27C256 optprom. This is controlled by a 4040 and that is fed via 74HC04 from a L/C oscillator incorporating varicap (varactor) diode tuning. There is also a 4538 in there as well, then we run off into the realms of the ADC and MCU, this will be dealt with at a later date, as I hate typing long winded stuff.
Comment