Noise-Reduction for Fisher 1266-X (evtl. 1270-X & 1236-X2)

[detectoman]

hi funfinder for great link, i came of see here, and this good site for obtain extense information on 1266 x fisher but not for 1225 x, btw, i appreciate very much, so i obtain other things for my needed, thanks of new, i understand 25' is bigfather of those, i am very amazed whit my fisher, due these is in any fields major than xlt, due the xlt, faulth in hot sun, but good discriminative function in fresh, i look the circuite of fisher 25" x, is intermedium in old and news models , very strong and fine sound, lightweight, problem is hot" receptor sistem, so detect mineral in any times, go far whit pinpoint sistem push botom, ok i await for new tips of other users on modification of 25 x" but exist no much 25" dinosaur earlier in the world, wtb, whit mineral disase, i prefer my fisher to other
economic batery duration, sound stronge, weight, dinamic, body balancead, 2 simple knob, check batery simple, shock resistant, not bss etc an embrace and of new thanks

[hoardhunter]

Hi, I,ve just joined the forum and I can,t seem to message member funfinder I have read some of his threads on the fisher 1266x detector and would like to ask his advice , can someone help me contact him thankyou, neil.. If some one could pass my mobile number on I,ll call him straight back, thankyou, neil.. 07948344482

[Qiaozhi]

Hi, I,ve just joined the forum and I can,t seem to message member funfinder I have read some of his threads on the fisher 1266x detector and would like to ask his advice , can someone help me contact him thankyou, neil.. If some one could pass my mobile number on I,ll call him straight back, thankyou, neil.. 07948344482

You cannot contact other members until you have made at least one post. You have just done that, so please try again.

[dejavuband]

Can you identify these components please

Hi ive done pretty well much of the mods on this thread(and by the way what a great thread)few mods left to do,but for now i pretty much know what all the trim pots do except the one with yellow insert by the wired ribbon, closest trim pot to it would be the tone pot,does anyone know what this little trim pot does?and ive noticed up by the ribbon hidden away at the top by pots there's a bulb or a valve,any ideas as to what the bulb is as it don't light up and is bothering me now, that's it for now ill leave it with you boys,but im not finished not by a long way,cheers

[Altra]

That light bulb is part of a battery charging circuit. So it won't light under normal operation.

Its an old trick to regulate current while charging nicad batteries. A charger is connected through a series diode and light bulb to B+. When a low battery is connected to the charger there is a large voltage differential. This causes the bulb filiment to heat up and the series resistance to increase. As the battery voltage increases to full charge the voltage differential, and series resistance decreases. This creates a constant current over the full charging cycle. I know too much information

[kt315]

Altra, in the case the bulb is working like BARRETTER.

[Altra]

I never heard of Barretter or don't remember.

After looking it up, yes it works the same.

[dejavuband]

re barreter

Thanks for speedy response,any idea what the small trim pot with yellow insert does,and any ideas as to why my threshold sometimes speeds up and slows down and sometimes goes completely?

[Funfinder]

thx dejavuband you liked this thread and
great that the mods are working fine for you!

Also haven't any idea for what the yellow pot is.
But so far I have the following describtion and
would be great if someone could complete it.

[dejavuband]

RE

Hi any ideas where i can get a push pull sensitivity pot as two tags have corroded and snapped off on mine,using a linear 100k pot with resistors to get the gain but for some reason the threshold keeps drifting,any ideas as to why this would happen ,cheers,are you in uk or states?

[Funfinder]

> the threshold keeps drifting

If this drifting is too strong you should find the culprit.
Bad batteries, the voltage stabilisation circuit, changing
electrosmog, bad resistors or even lose soldering contacts.


Have no idea where you can find such a special push-pull resistor,
but you could attach 2 seperate pots somehow (if you don't need
this battery-check button, there would be space enough).

If you're skilled you also could try to repair the push pull tags:
Use a little knife and remove the plastic around the region
where the tags broke off until you have enough metal for
soldering contacts. But you have to fix the wires for this
contacts first with glue etc. or they may break off again.

I could already repair an IC with broken leg with this method.


btw. the PCB I have is different, theres just 1 variable resistor in
the corner. Perhaps yours now has 2 different pots for presetting
each of the both discs.

[Funfinder]

Because I opened the Fisher 1266-X for the above picture
now I also took a second one from the PCBs back:

On the left side the already know 40 nF capacitor and the
both connection wires to the variable push pull resistor.

http://www.geotech1.com/forums/showp...9&postcount=20

As far as I can remember the 1 MegaOhm Resistor in the
middle also has to do with reducing the noise.

And the very low value cap (I guess around 5-20 pF)
was soldered parallel to either the transmission or
reception coil contacts (I guess reception) so the
Fisher 1266x no longer discriminates very small rusty
iron parts (5mm diameter).

btw this mod also slightly improves the sensitivity to other
finds by some percent (iron ca. 10% < - -> silver ca. 5 %).

Perhaps the 8'' spider coil finds such stuff by default
because of slightly different "calibraton" (coil impedance)
but I haven't this 20cm coil that's why I can't test it.


One big advatage of the Fisher 1266-X is:
It uses just a few electrolyte-condensers (or just 1 - 2)
and those are not too big. With some luck this machine
still works very good after 30 years.

Only the coils cable isn't very flexible enough and could
break - especially if the temperature outside is very low.

But it's a really well made machine and it's "magic spirit"
lives on in the great improved bulgarian Blisstool circuits.

[satdaveuk]

I got the 1265x which was givin to me a while ago in exchange for repairing a Arado and apart from changing the on/off pot 10k and battery holders x2 the machine works like a dream, still dig crap mind you like any machine.
They were certainly ahead of there time compared to most others on the market, correct me if im wrong in saying the 1266x is the same but SMD devices were used.

Regards

[Funfinder]

Hi satdaveuk!

There is not much difference as I've found out here:

http://www.treasuresearcher.com/comm...ead.php?t=1682

I have used the 65 for 11 years and now the 66 for 8 years and there
is not much difference. The 66 may go a little deeper, the sens knob
pushes in for max - great change from the 65 as I was always bumping
it in by mistake. In general, not much difference - I love my 66 and
do not plan on getting anything else in the near future. Steve in so
az

http://www.thunting.com/smf/fisher_m...-t13231.0.html

the difference between a 1266x and a 1265x is the black face on the 1265x.
1266x comes with a spider coil and the 1265x comes with a concentric solid coil.
i give my 1266x an edge over my 1265x.

here the Fisher 1265-X is better than the 1266-X at the 5 pence test:
5 pence sterling. Mass, 3.25 g. Diameter, 18 mm. Thickness, cupro-nickel:
1.7 mm nickel-plated steel: 1.89 mm. Edge, Milled.
http://www.staffsmetaldetectors.co.uk/5_pence.htm

Both don't use any SMD parts.

Below an original info - 20 years old! Almost a rarity today.
I still have alot of such old info-material from all kind of MDs.
In Middle Europe the 1266-X had a price of 1800 german marks,
today this would be ca. 900 Euro but I got mine second hand
directly from the dealer for just 300 Euro in todays money and
it still works great - a nice n' still working trusty rusty memento!

btw. here the dephts of some other MDs of this time
incl. price - but I hardly doubt those coin depths...


White's AF 101: coin:10cm - copperpot 80cm:50cm - 115 Euro

White's Beachcomber 60: 15cm - 70cm - 340 Euro

White's Eagle II SL: 45cm - 180cm - 1480 Euro
-""- with 38cm coil: 55cm - 210cm - coilprice: 180 Euro

Garrett ADS 7X: 40cm - 160cm - 1200 Euro
-""- with 32cm coil: 50cm - 190cm - coilprice: 160 Euro

[satdaveuk]

Hi
So apart from the coil all seems the same, i got circuit somewhere for the 1265x but not the the 66 would of be nice to do a comparison just for interests sake... anyone?
I think it was the 1280x that was made with smd components although doesnt seem as popular im not quite sure reason i read these tests with a very open mind because ive seen machines that i actually own been underated due to operator not knowing what hes doing.

Regards