fisher 1200 series coil wiring

[maddogchilli]

Strip all wiring.
4 wires in all.
White wire with outer earth.
Red wire with outer earth.

White goes to no1
Earth goes to no3

Red goes to no2
Earth goes to no4

All numbers are on the bottom of the connector plug.

[WM6]

Good works, thanks!

[kt315]

pinouts of 1200 series coil for whom need https://www.ebay.com/itm/Fisher-meta...rf8:rk:45:pf:0

[homefire]

Don't remember where I found this. Most likely here on Geotech. It's helped me out a few times now.

FISHER COILS ???? (- General)

by Dave J., Friday, November 18, 2011, 04:40 (1 day, 6 hours, 58 min. ago) @ BIG SILVER CLARK

Over the last several years we've introduced a lot of new models in several different product lines. At times it has resulted in some confusion as to what's what. Knowing firsthand what dying pains feel like, I prefer the pains that come with growing.

So much for editorializing.

* * * * * * * *

The F2/F4 coil is electrically the same as the legacy BH series. But with a CB mike style connector. Nowadays. Originally it had a BH compatible DIN connector and is still available in that configuration for BH and original F2/F4 machines.

It is not electrically compatible with other Fisher or Teknetics products. It probably won't damage them but will NOT work correctly.

If someone has coils they can't figure out what's what, here's the straight skinny: get an LCR meter that tests at 1 kHz. And probe around the contacts until you find what is obviously the transmitter.

F2 Series: Receive coil (pins 1 and 2) is 2.4 mH , R = 5 Ohms.
Transmit coil (pins 3 and 4) is 2.4 mH in parallel with (220 nF + 22nF), resonant at 6.6 KHz. DC resistance of coil is 8 Ohms.
An alternative TX would be 220nF and 2.65 mH, though I haven't tried it.
Capacitors: the 220 nF would be best if polypropylene, though polyester/mylar would be OK. The 22 nF will be fine in polyester (and could be 20 nF)

Legacy BH series: approx. 2.4 mH.

T2 only: approx. 680 uH, center tapped with some positions reading about 170 uH.

F75/F70: approx. 660 uH.

GB, GB Pro, G2, F5, Platinum, Gold, Gamma, Alpha, Omega, Delta: approx. 880 uH. Concentrics in this series are NOT specified for use on the GB, GB Pro, or G2 although in some instances they may seem to work.

If this information was useful to anyone please let me know by posting here.

--Dave J.