Fisher 440 series

[ivconic]

Need some detailed informations on old Fisher 440 series VLF All Metal detector.
Some photos would be nice to post here also.
By strange coincidence i got its pcb with all components, looking brand new, never used!? But i dont have enclosure,coil and dont know what front panel look like?
I have some schematic posted earlier here on this forum.
Although it is a bit obsolete, vintage you may say, i am "itched" to retreive it to life. Would be nice and huge pleasure to make it work again.
Any coil informations? Any other informations? Any experiences?Photos?

Carl do you have it in your huge collection? Is it possiblle you to measure coil inductances and resistances and sizes? Thanks in advance!
I tried to locate some info about it on internet...yet without success
Help here!
Regards!

[Eugene52]

Fisher 440 series

Need some detailed informations on old Fisher 440 series VLF All Metal detector.
Some photos would be nice to post here also.
By strange coincidence i got its pcb with all components, looking brand new, never used!? But i dont have enclosure,coil and dont know what front panel look like?
I have some schematic posted earlier here on this forum.
Although it is a bit obsolete, vintage you may say, i am "itched" to retreive it to life. Would be nice and huge pleasure to make it work again.
Any coil informations? Any other informations? Any experiences?Photos?

Carl do you have it in your huge collection? Is it possiblle you to measure coil inductances and resistances and sizes? Thanks in advance!
I tried to locate some info about it on internet...yet without success
Help here!
Regards!

Hello Ivconic , Is it a model 441 ???? Then It is 4.5 khz and model # is ISOCON IV , tuning is 10 turn multipot...............Let me know if this is it , or I will dig for something else !!!...............Regards.............Eugene52.... .stalni-clan

[ivconic]

Yes Eugene,that is the one, you posted. Thanks! Many thanks!
Do you have it? Or do you have chance to measure coils? Inductances and resistances?

[Eugene52]

Fisher 440 series

I sold mine on e-bay a few years back , but I am searching for the Fisher D-D search-coil specifications . I think the coil specs are buried in this forum here ???..If not , I will check the vintage forums and my Detector Data C.D.'S that I have !!!............Bye for now............Eugene

[ivconic]

Please let me know if you find any datas.
Many thanks again.
Regards!

[Eugene52]

Fisher 440 series

Ivconic , some good News , I found some information that might be a big help to you and answer some questions for me , and others !!!! The Fisher M-96 valve locator / metal Detector is "4.5 khz" and the search coil is 8 inch DD 4.5 khz ALSO !!!!! If a member of this Forum has a M-96 , they can kindly measure the DC of the RX and the TX ..........See the pdf file........Anyway , maybe Fisher kept using the 440 design for the M-96 ?? Specifications are on page 14 or so.....I will keep searching for the coil specs , but this pushes the answer a little closer......................Regards............... Eugene

[ivconic]

Yes, good thinking!
Thanks !
Looks simillar, could be a same coil? Or simillar?

[PhilBarnes]

Fisher 440 series

Hi IVCONIC
I first used a 441 back in 1977. I no longer have this detector.
It Paid for its self many times over. Then I got a GoldBug II, then a Fisher 443.

I do not use these anymore since I built my Hammerhead PI. I recommend building the HH and forget the old Fisher 440.

If you want to pursue the 440, I have 8" and 3" inch coils and I have an impedance bridge. If you want measurements just let me know which coil you are interested in and I can send measurements to you. I can photograph the 443 board for you but I don't know how to post photos. I don't know the forums policy of sending to email addresses.

Have fun, Phil Barnes.

[Qiaozhi]

I can photograph the 443 board for you but I don't know how to post photos.

When you select "Post Reply", scroll down the page and you will see a button labeled "Manage Attachments. Click on this button to add photos, but note the maximum sizes allowed for different file types before uploading.

[ivconic]

Hi IVCONIC

I first used a 441 back in 1977. I no longer have this detector.
It Paid for its self many times over. Then I got a GoldBug II, then a Fisher 443.

I do not use these anymore since I built my Hammerhead PI. I recommend building the HH and forget the old Fisher 440.

If you want to pursue the 440, I have 8" and 3" inch coils and I have an impedance bridge. If you want measurements just let me know which coil you are interested in and I can send measurements to you. I can photograph the 443 board for you but I don't know how to post photos. I don't know the forums policy of sending to email addresses.

Have fun, Phil Barnes.

Wow! I will be gratefull to you if you do that! I am interesting in both coils datas.
I wouldnt pay any interest on 440 schematic at all - old and obsolete, but i have its original pcb with components, looks like built yesterday, not even a dust on it. So i was thinking to complete it and keep in my collection as workable detector.
I will figure out some nice enlosure for it and the rest what needs, but need coil datas so i can build my handmade to connect on pcb...
So...please do measure inductances and resistances and let me know. Post here so others can see and have those too.
Very best regards!

[PhilBarnes]

Fisher coil info.

8" coil. Transmit coil: 25.7 Ohms DCR, 12.6 mHy, Q=3.0 @ 1kHz. Center-tap to cable shield.

Recieve coil: 25.7 Ohms DCR, 12.6 mHy, Q=3.0 @ 1kHz. Cable shield connected to start or end of winding.

3" coil. Transmit coil: 25.6 Ohms DCR, 12.6 mHy, Q=2.4 @ 1kHz. Center-tap to cable shield.

Recieve coil: 25.7 Ohms DCR, 12.6 mHy, Q=2.4 @ 1kHz. Cable shield connected to start or end of winding.

The coil housing needs to be faraday shielded between the windings and the ground side of the housing. Fisher uses aquadag high resistive paint connected to the cable shield to shield the coils.

[ivconic]

PhilBarnes THANK YOU man!

[gdmellott]

I'm looking at a Model 441. Serial # 78 67846. The power seems to differ significantly. Though there is 2 9 volt batteries; they don't seem to be in series like the schematic above suggests. Rather both grounds are apparently together. Since this is what I'm have trouble repairing (one wire failed then others as I kept digging into it). I am pretty certain the two black wires were together and the red one that failed later came off of what you are designating here with the ground plane symbol. There are other part differences, such as a two transistors feeding the audio output. (A 2N3638, PNP, .5 Amp is added.) When I get a better check on things I'll try to present something more clear.

[gdmellott]

Here is the difference I noted

[gdmellott]

I'm having some troubles with my internet connectivity in the evening that can even require me to reboot by DSL port. Anyway, critical differences my by in C1777 usage and which pins ofn IC7's input get what. The audio circuit is different and easier for me to follow how it works. Should one wish the have the image of the PC board circuitry I used I'll supply it. It's 1.7+ MB though. So I didn't wish to load this server for nothing.
Sincerely, Gregory D. MELLOTT