Fisher F75

[bernte_one]

Hello,

found this:

http://md-hunter.com/fisher-f75-circuit-diagram-board-layout/

maybe someone can store this Pictures for the Forum here or on local hdd

[Koala]

Nice link. Some other interesting things poking around the site.

[brs]

The differences between the versions in speaker
2262A _ fisher se gold
2262c _ fisher 75 se balck
max 4477 ASA _ FISHER 75 se BALCK

http://c.top4top.net/p_4150lh4b0.jpg

http://d.top4top.net/p_415yus7q1.jpg

http://e.top4top.net/p_415az29v2.jpg

[kt315]

KROT printed http://md-arena.com/samodelnyj-metal...vitelnye-foto/

[DavidB]

What they are calling -5V from the output of the rail splitter would actually be 2.5V from what I can see. The 3.3V regulator also has a odd way of coupling the input voltage.

[sinclairuser]

saved for posterity, though its only for repairs really as we have no firmware.

[brs]

Max4477ASA fisher 75 black
2262c fisher 75 gold
My friends the loudspeaker which is the most stable I have for black fisher and i want to switch ic

[brs]

Hello friends
fisher 75 se Is there a difference between the loudspeaker max 4477 and the other 2262c, whichever is the best in performance and one of the pictures used 2262A Thank you

[Melbeta]

Yes, there is no firmware (operating embedded software) supplied in this F75 material, but with a data stream logger, connected to the output of the chip(s), one can extract the embedded commands (unless they are encrypted), determine the beginning checksum of each line command, the ending checksum of each of the lines of command, line them up, execute them and see what each line of command does, and then a good software engineer can then write new software. I am not encouraging anyone, just stating what reverse engineers do when they examine a project. The fellows in Brazil used to build fantastic data logger units...

Now when encrypted, it takes a lot more work to figure out the command lines and their parameter commands. But software engineers understand encryption!

My former son-in-law, a reverse engineer (now lay-ed off and working for himself) for a chip manufacturer, used to be in charge of the reverse engineer division of a large un-named chip plant, and I am just letting some know of the possibilities. Then then took the chip apart, layer by layer, re-constructing each of the burned fuses, and viola, they had stripped out the programs themselves. And some of the chip programmers from Asia, had an ability to read the assembly code inside secured chips! But this was back in the 1990s time periods. I did not believe it myself, until I saw the extracted assembly code from some secured chips.

Now I will not say more, but there was a Russian fellow, over here getting his doctorate, and he was the master of the reverse engineering of the Motorola microprocessor chips. I heard he had everything in as little as two weeks.

You see, the impossible just takes a bit longer...
Melbeta

[dbanner]

anyone who has the skills to do all that could as well design his own superb metal detector. or maybe just go out and buy one.

[chesters4]

Vsorry to hyjack the thread but its not worth one to itself.
My red push switch on my F75 is getting intermittent ,i opened it up but was surprised its not a standard push to make switch ,unfortunately on the inside all you can see is a blob of hot glue and 2 wires so no indication what the switch looks like ,can anyone show me a picture of a replacement switch as prising off the hot glue best done when a new switch is bought we cant have weeks of waiting for one to turn up the weather is still fine over here in the UK thanks ,Dave

[Carl-NC]

It's a tactile switch, NKK JF15CP2C.

https://www.digikey.com/products/en?keywords=JF15CP2C

[Mark-VA]

Interesting, I wonder it that might fix an Explorer SE that has a sticking button. But it might be an embedded switch on the main board.

[Carl-NC]

SE has a membrane keypad, you replace the whole thing.

[Skippy]

Thanks for posting the pushbutton info, Carl. I always thought a black button would look best, on both the T2 and F75. The T2 grey colour is an unattractive choice, the F75's red would be better. A shame the manufacturer can't (cheaply) make custom button colours.