Vector Trek Mini Eliminator II
The full report for the Vector Trek "Mini Eliminator II" is not finished. However, some people might find this preliminary information useful, or maybe just entertaining.
Currently, this LRL is sold exclusively by Bob Fitzgerald in Reedsport, Oregon, but the Vector Trek company is owned and operated by Neil Pagel in Chino Valley, Arizona (4255 W. White Rock Road Ph 928-636-1292). The Mini Eliminator II sells for $1895.
The M-E II consists of a transmitter unit, a multimeter, and the obligatory pair of dowsing rods. The schematic for the transmitter unit is as follows:
The transmitter is designed around the Intersil 8038 function generator chip and the basic hook-up, for the most part, is directly copied from their data sheet. The output of the 8038 (pin 9) has some additional circuitry hanging on it.
The "Target Reflection Nullifier" (TRN) switch energizes one-of-two NMOS devices which switch in a 10-megohm load resistor. There are two funny things about this. Both positions of the TRN switch add in the same value resistor (10 megohms), albeit using very slightly different NMOS switches, so there is no difference between TRN-on and TRN-off. Also, adding 10 megohms to ground affects the signal only 0.15% because of the 15k pull-up resistor. In other words, the TRN circuitry has no real effect on the signal.
The other switch is a "Hi-Med-Lo" setting. It is probably intended to switch in 3 different high-value load resistors. On the PC board, there is a 10-megohm, a 22-megohm, and 2 more 22-megohm resistors. I suspect it was intended that the 2 additional 22-megohm resistors be in series, for a total of 44-megohms. However, the PC board layout has one of the 22-megohm resistors completely shorted out, so that it does nothing. Again, the values of these load resistors are so high they have no real effect on the signal. Also, though I have shown in the schematic the rotary selection switch as it was probably intended to be connected, in reality two of the load resistors were soldered to the wrong lugs of the switch, so they never get switched in at all. Therefore, those two switch settings are just open circuits.
Finally, the output signal has 5 inductors connected to it, almost in a manner of a bridge connection. Except that only one node of the inductor bridge is connected to anything at all, so no current can flow through it. Also, the center inductor has one end completely disconnected. But it does have a magnet glued to it. Bizarre.
Workmanship is shoddy. Already mentioned is the mis-connected rotary switch, and the shorted resistor. Soldering is sloppy; the wire that feeds the ground rod jack had only 2 strands of the wire actually soldered. Other wires were easily breaking loose during disassembly. The electrolytic capacitor on the output of the 7905 regulator was installed backwards. This can sometimes cause electrolytics to explode. The other electrolytic capacitor is connected to the wrong side of the 7805 regulator; it should have been on the output. Epoxy was sloppily glopped on to the PC board, to prevent inspection of the circuit. Fitzgerald's web site declares, "The locators are built by some of the best engineers in the USA and are professional grade." The design and workmanship of the Mini Eliminator II indicates that the engineers Fitzgerald relies on are incompetent.
