Fisher F2 Ground balance mod

[brudulje]

hi, i just bougth the fisher f2 and open it up, and as stated in another thread its the same pcb as the F4, minus some things..and i noticed that there is a place for the ground balance pot like on the F4, but instead there is a regular resistor there giving it a fixed value...
the resistor is 20 ohms.

So, is there anyone out there who have open up a F4 and can tel me how mutch ohm the ground balance pot is?



all help and tips welcome

[Skippy]

It's not as easy as you think. The F2 membrane keypad has conductive tracks that run above the hole in the front panel, so just "fitting a pot in" won't work.

[brudulje]

It's not as easy as you think. The F2 membrane keypad has conductive tracks that run above the hole in the front panel, so just "fitting a pot in" won't work.

well iwe tried to use a strong light source and i cant see any tracks in the hole...but anyways if it is i will just make another hole for the pot and use wires from the pcb to the pot...the fixed resistor is only 20 ohms, im gonna order me a 47 ohm pot and a 100 ohm pot and give it a try =

[Dave J.]

Ack! Don't do it, you could smoke it! (Sorry I didn't see your post earlier, hope I'm not too late.)

The ground balance pot is 10K.

--Dave J.

[brudulje]

nice!

thank you mate! iwe havent done anything yet, so thanks for the info! =) i was gonna solder out the resistor and do some more research before modding..and ofc use the f2 some first =)
now im gonna order me a 10k panel pot

[yourvibes]

f 2

now done. . many thanks for that. . been running mine from 12 v converyted from old drill . .lost power gauge but seems alot more perky !

[brudulje]

nice!

cool, so you have confirmed my suspicion about that it is acualy no treads in the membrane over the pot hole...hehe.
stupid slow postage in norway still waiting for my potentiometer...

[yourvibes]

f 2

yes there is a track exactly in line with hole but just make hole below track. . . if or when you strip it apart put membrane back on and you will see from behind ,, so adjust to suit. . used 10 pot ( measured 9.4 ) was just a part i had lying around and ive also been using 12 v for around 5 months now ( saved lots not buying 9v battery's ) but its knocked battery indicator out ! but works well.. very well.. sorry about fotos , dont know what happened to size !!

[Skippy]

I had no reason to decieve you when I stated there was a track on the membrane. It does not go straight across the middle of the panel hole, and fitting the pot offset, or using a smaller pot, possibly a 1/8th inch (3.15mm/3mm) shaft model is viable.

[yourvibes]

f 2

hi . . no probs, , there is a track ** exactly** on the original hole .. i had to elongate the hole and solder the pot on an angle or as you say you could use a (different size pot )(but you will still have to elongate the hole ) or mount it elsewhere ! ... for anyone else interested to open the case of the f2 peel the front panel off from the power button side first !!!!( make sure you get all layers ) or you run the risk of damaging it because the connections are on the discrim side. . ! ps the parts i used were only bits i had taken from something else .hope this helps someone and sorry about fotos ? very interesting results.. i need a bigger coil now for extra depth ..modern 5p at 8 inch's with standard coil ( in air ) . . also silver coinage numbers have changed slightly ( george 111 shilling was a solid 67 before mod now 73 all silver coinage ive checked have changed,,,, but gold ring still 37 )

[yourvibes]

f2 g b mod

seems to me a very worthwhile mod .... many thanks to anyone whos gave any ideas or any input

[Skippy]

It's worth pointing out that you don't need to remove the label/mebrane completely, you can just tease it away for 3cm where the two screws are located. The screws don't even need to be removed, just undone. Then it can be returned to original condition with hardly a mark on it.

[lucir82]

Fisher F2 Ground balance mod

Hi, i am really interested about this mod, could use a GB feature on my F2. The problem is that i am a little scared of the possibility of failing. Has anyone else modded his F2?
Thanks for all of the info above (and below )

[Kbron2000]

WOW! I wish you can post a video on how well it works!

[Kbron2000]

Can you share a pic of the Grnd Pot location? Thanks