King Cobra PCB

[shre14146]

Hi kt315
Can i replaced LM2930-08 with 7808
Best regards.

[mayky]

in 7660 ics not the same


This Ic-s works fine, the neg voltage is : -6,8 V

http://www.aliexpress.com/item/Free-shipping-20pcs-ICL7660SCPAZ-ICL7660-IC-REG-SWITCHED-CAP-DBL-INV-8DIP-Best-quality/1879620656.html

[mayky]

Do You want to know why was noisy my cobra?

Because it is not the original IC kit was used.
Instead L308 NE5534
Instead LF442CN TL082
The NE5534 is too large load will be driven to a negative voltage.
The TL082 something strange insensitivity causes. The nearby things do not see but a far things see.
Who have problems with noise, try to replace the original type ICs.

[kt315]

Schematics covered by King Cobra board:

GMT:
King Cobra
GMT1650
Gold Scorpion – most likely, no data
Thunder Stick – most likely, no data

Tesoro:
1980: Deep Search VI, Deep Search IV, Deep Search VII
1981: Aztec, Cortes, Amigo
1982: Scout, Mayan
1983: Inca, Silver Sabre
1984: Sabre II, Sabre Supreme, Silver Turtle
1985: Golden Sabre, Cutlass
1986: Silver Sabre Plus, Eldorado, Royal Sabre
1987: Toltec 100
1988: Toltec 80, Diablo, 4 Reale, 8 Reale
1989: Golden Sabre Plus, Lobo
1990: Bandido, Pantera
1991: Diablo II, Silver Sabre II, Stingray, Laser B1
1992: Cutlass II, Golden Sabre II, Laser B2
1993: Bandido II
1994: Toltec II, Sidewinder
1995: Piranha, Stingray II, Laser B3
1996: uMax Bandido, uMax Cutlass, uMax Diablo, uMax Sidewinder, Amigo II
1997: Shadow X2, Lobo SuperTRAQ, Laser PowerMax, Bandido II uMax, Silver Sabre uMax
1998: Cutlass II uMax
1999: Sand Shark, Laser Rapier
2000: Conquistador, Compadre, Golden uMax, Tiger Shark
2001: Cortes, Conquistador uMax, Eldorado, Euro Sabre, Silver uMax
2003: DeLeon, Tejon
2004: Cibola, Vaquero

[kt315]

silver sabre - I found in a dutch book of metaldetectors :
tx 100 turn of 0.5mm copperwire and a diameter of 200 mm and
rx 170 turns of 0.5mm copperwire, diameter 80mm

DD_255x137.pdf
coplanar_decrypted.pdf

[kt315]

do not ask me more

many times answered on this matter.
Cobra was choiced by me TO COVER ALL TESORO models be cause the pcb is looking optimal and perfect, Cobra has 2 tones and NOTCH filter. so all tesoro coils with 6mH RX TX will fit Cobra.
====
Tesoro concentric
Tx 1,5 5.7mH 22 ohms -- Rx 3,4 6.2mH 22 ohms
====

TGSL_DD coil.pdf
TGSL DD Coil Making.pdf

[TANCE]

How do Coil

[kt315]

reply of Monte The Gold Mountain GMT-1650 and the Cobra were Posted by: Monte [ Send a Message ] Date: October 28, 2015 07:14AM

Registered: 10 years ago Posts: 5,944

the same models with the toggle-selected expanded low/high Discrimination adjustment.

The King Cobra was different in that it had the Notch Disc. circuitry and lacked the selectable expanding Disc. range.

In descriptive terms, the King Cobra, a too-close copy of Tesoro circuitry for the Golden Sabre Plus units, also operating at 15 kHz, had the more limited lower Discrimination adjustment. That was before Tesoro went to the ED-120 for a bit lower-end adjustment.

The Cobra and GMT-1650 had the broad Discrimination that allowed a minimal acceptance, ferrous and non-ferrous, similar to the Tesoro ED180 term for All Metal Acceptance at the minimum Disc. setting. The Cobra/GMT-1650 was one of the best models I ever used for being able to "fine tune" the rejection desired, especially in iron littered old town sites, homesteads, and urban renovation, etc. I was one of the GMT Distributors when they came out and I mentioned the one major thing they goofed on was not adding a Threshold control for the All Metal mode.

Sadly, Gold Mountain Technologies major errors were really poor marketing decisions combined with irritating Jack Gifford at Tesoro for the circuitry issues. Too many bad moves when they had some models that could have grabbed a certain niche of the market. I wish they were still available, and easily/affordably repairable. Of all the long-gone manufacturers, that is the one model (Cobra or GMT-1650) that I wish I still had on-hand with the smaller coil for dense trash.

Monte

---

"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells
Just a name that brings back fond memories of old alkali desert favorite sites in Utah, Nevada, and Eastern Oregon. There is no pastime I enjoy more than hunting old sites as best I can, doing research, and helping others learn more about this great hobby.:

Compass Coin Hustler and Compass 99-B
(For seminars and occasional use.)

... and my 'Ready-to-Hunt' buddies ...
Makro Racer w/'OOR' DD
**This space reserved for a Nokta Impact.**
Teknetics 'Classic' T2 w/5" DD
**This space reserved for a Teknetics Omega 8500.**
Tesoro Bandido II and Bandido II µMAX each w/6" Concentric
Tesoro micro-housed Eldorado w/6" and 8X9 Concentrics
Tesoro Silver Sabre µMAX w/6" Concentric

[email protected]
(503) 481-8147(503) 481-8147

[kt315]

====
Tesoro concentric
Tx 1,5 5.7mH 22 ohms
Rx 3,4 6.2mH 22 ohms
====
================================================== ==============================
Tesoro
Name TX-L TX-R (ohms) TX-fo TX wire RX-L RX-R (ohms) RX-fo RX wire
--------------------------------------------------------------------------------
Brown 8" 5.59mH 21.2 --- --- 6.23mH 22.1 --- ---
White 8" 5.68mH 21.8 --- --- 6.36mH 22.8 --- ---
White 4" 5.62mH 26.6 --- --- 6.13mH 28.2 --- ---
uMax 9x8 5.74mH 24.6 --- --- 6.21mH 25.8 --- ---
uMax 12x10 5.78mH 17.3 --- --- 6.15mH 18.9 --- ---
DD 11" 5.90mH 19.8 --- --- 5.38mH 18.4 --- ---

[ava_61]

[Toros]

Specifications Coil King Cobra !!!???

Look at post №47.

[ava_61]

Specifications Coil King Cobra !!!???

[kt315]

its simplest noiseless RC filter you can see in much projects. also, some SMD's give the beginners
some practic to solder and not fear SMD. in projects I have to orient on lowlevel enthusiasts, not on gurus, just cause
them majority.

[mayky]

That would be a short-circuit.

[kt315]

thank you. seems OK. would like to look an orientation of R79 R80, be cause guys did a mistake setting them 180 grad rotated.