Minelab Goldseekers 15000

[Tepco]

Now this is puzzling really, considering how old is this topic. Did anyone crack full schematic? Everything is quite obvious, opamps, comparators etc. but what on Earth is chip marked "3" on schematic, and what this part of circuit actually does? Not opamp, even strange pinout one, not analog switch, transistor array, perhaps maybe some old and not too much used analog multiplier circuit or something alike? (MC1494 not fit, LH0094 either...) Even worst, +V pin is not specified (2,3,4 are candidates, 15 is typical) many 16 pin chips use pin 5 for -V. Usually W.L. schematics know to be reliable, but this one... Any idea, just for curiosity?

BTW. U2 is comparator (393) not opamp, IC4 is mistake.

[Altra]

whoops already posted

[Altra]

Candy used this in the SD2000. Maybe IC3

[WM6]

Maybe mysterious chip marked "3" is only known 4060 (if we assume that WL can make some mistake).

[Tepco]

Well may be CA 3083, makes sense, i never considered it, Thank you!

[WM6]

Candy used this in the SD2000. Maybe IC3

Very likely.

[DIRCEU]

Hi again.
I prefer to use in my experimens old opamps type TL06x, TL07x and TL 08x because they are very cheap in Bulgaria and operate enough fast. The sign "x" means number 0, 1, 2 or 4.
In my opinion, the Goldseekers 150000 circuit will operate if you experiment it with following ICs:
IC1 - TL072 or similar
IC2 - TL072
IC3 - two ICs which are different type. The left one IC3 has no supply leads. That forced me to think it is a transistor array. The right one IC3 operates as changeover switch like CD4053. May be the operation of this part of circuit is described in an old Minelab patent of Bruce Candy.
IC4 - according pin numbers, IC4 are two separate ICs. In this case they can be TL061, TL071 or TL081. However in my opinion, Bill Lahr made mistake and IC4 is a double opamp IC.
IC5 - TL082
IC6 - TL084
IC7 - operates as powerful voltage follower with output impedance 2.5 ohm. I think TL084 will do the job.
IC8 - TL072.
However my advice is not to vaste time with such obsolete design.

Hi! mikebg

I am very grateful for his kindness in answering me and based on what you said, I think it is better to search a little more about this detector before starting to build it.

Best Regards

Dirceu.

[Tepco]

Very likely.

It is 3083, but whit error in schematic. Pin 6 of right "3" chip is unconnected, should be tied to pin 10 (i suppose) in order to work.

[goldie]

Does anyone have a photo of the board from different sides? Tried building this?