Validated/Certified F75-2

Good info Rod..

The only thing about a F75 Vs a Cz is that a CZ can be calibrated on the bench...

Pretty sure a F75 is hardwired...

Keith

Steve Herschbach Wrote:
-------------------------------------------------------
> canslawhero Wrote:
> --------------------------------------------------
> -----
> > You're providing a great service Tom, and
> judging
> > from the response Fisher should be embarrassed.
> > Can you publish the basic battery of 9.0/9.1
> air
> > tests that others have used for your certified
> > unit? That would be a useful starting point for
> > folks who get a new unit in the future....
>
> Very sad. The entire idea that a brand new
> "flagship" detector should need double checking to
> make customers comfortable says volumes about the
> current state of affairs at First Texas. I think
> one big reason First Texas purchased Fisher was to
> escape the stigma of the Bounty Hunter name by
> associating the product with a name long respected
> in the industry. Between the Gold Bug, F19, and
> now F75 however I think they have done irreparable
> damage to the brand. I know that from now on when
> I think Fisher, I will just be thinking "Bounty
> Hunter with a different sticker". I have hung in
> there as long as I could but I personally have
> lost faith in the ability of the company to
> deliver consistent, quality product.


the engineering design can be outrageously good,.
HOWEVER,quality control IS everything!

(h.h.!)
j.t.

[www.dankowskidetectors.com]

[www.dankowskidetectors.com]



Edited 1 time(s). Last edit at 01/28/2015 02:24AM by go-rebels.

Keith Southern Wrote:
-------------------------------------------------------
> Good info Rod..
>
> The only thing about a F75 Vs a Cz is that a CZ
> can be calibrated on the bench...
>
> Pretty sure a F75 is hardwired...
>
> Keith

so a certification would just show whether your F75 is good or bad? and to what extent? Tom, what does a certification entail for one of these bad boys and can you actually improve them?

Hey Slaw..

Although Hardwired.

One thing that can be changed is the coils...One Bi-Axial may mate to one F75 better than another and Vice Versa..So some swapping of coils and finite measuring could help a unit ,,,

Keith

Keith, very true....I recall a lot of folks talking about their upgrades and mentioning that they got a new coil with it...

and maybe, since you've got a killer unit, they spent some time matching the coil up on yours, a 'special'...that would take a lot of extra time that they can't afford to do normally....



Edited 1 time(s). Last edit at 01/28/2015 02:52AM by canslawhero.

Troy needs to get back in the game.

you Know whats funny though..

I can take the coil of a Gold Bug pro 11" Biaxial and put it on my F75 and I cant see any difference...

But as I was saying earlier besides returning a KNOWN subpar unit the only thing I can think of to maybe help it on our own would be to swap coils...

I think the major part of the 11/14 Vs12/14 is on SOME of the 11/14's the actual boards and also maybe the coils were not assembled correctly...maybe just one little resistor out of tolerance was throwing things off????

I know my 7/14 had the worst all metal imaginable...berzerk EMI even on zero sens...

My 12/14 has the most sweet all metal Ive ever heard on a f75, on 99 sens to boot..

disc sides on the 7/14 Vs the 12/14 was about the same...the 12/14 maybe a little hotter on all modes except FA...I think my 7/14 FA mode was a tad bit deeper...

Something went wrong in the Assembly section of the product around November ..and seems to have straightend up around December..

When I got hold of my 12/14 I called back to First Texas and told them to hold what they had.. dont mess with it..


I hope everyone gets a Proper F75v2 and Tom is a good avenue for one....I hope everyone gets even better ones than can be imagined..

Keith

In the Navy I was responsible for the calibration and testing of several key systems and components. I have worked for companies that make components for embedded medical devices that required the strictest of quality testing procedures. In both cases over time processes changed as issues where identified and standards tightened or tests changed to improve performance and ensure quality.

Even the best test and process has room for improvement. My guess is Fisher is not making purposeful mistakes. Instead I guess their testing process allows for too much variability in the end product. It is very possible if the returned unit was run on the line like a new product it would pass again. The good news is returns go to techs not the production line I am guessing.

Anyone who has worked in electronics manufacturing knows that the quality of a refurbished product is almost always better then one straight off the line. Line testing is designed to be efficient and effective but is almost always performed by a production worker trained to do the test or process. Refurbished product typically go to a true technician who usually has a broader background and understanding of the test performed and is often tasked with determining the cause of the return. For this reason I have no issue purchasing manufacturer refurbished products

Fisher just may need to make a change to the production line testing and calibration process. Something in the testing and calibration is not catching issues that come up in the field. Maybe they should hire me as a consultant so I can tighten up the process and reduce variability in the end product.

I work for detectors plus expenses :-)

Bryanna - Nebraska

Current - New to me but not new MXT Pro and T2 SE2 - Previous Minelab Sovereign GT, Minelab Safari, Whites DFX, Whites Eagle Spectrum
Smile its a good for you!

The F75 is a microprocessor driven platform; subsequently, nothing to adjust. This leads to a 'go / no-go' scenario.

Bryanna = True words. And I'm certain the design engineers cringe when their original design blueprint/intent ..... is sent to the manufacturing & assembly line ........ of which/then, ends up being built incorrectly....... then ends up having errors in the final product. Makes the engineers look bad............... when............ in actuality............... the error had nothing to do with the original design/intent.

Keith said:

"I can take the coil of a Gold Bug pro 11" Biaxial and put it on my F75 and I cant see any difference... "

yes, now that is surprising! 13kHz vs 19kHz, impedance issues etc and you see no difference. I'm very confused on that one.

Keith, could you try the 5x10 off of your F19 on the F75 and see how it does?

I'm curious if it works as well as your F75 specific 5x10....

canslawhero Wrote:
-------------------------------------------------------
> Keith said:
>
> "I can take the coil of a Gold Bug pro 11" Biaxial
> and put it on my F75 and I cant see any
> difference... "
>
> yes, now that is surprising! 13kHz vs 19kHz,
> impedance issues etc and you see no difference.
> I'm very confused on that one.
>
> Keith, could you try the 5x10 off of your F19 on
> the F75 and see how it does?
>
> I'm curious if it works as well as your F75
> specific 5x10....



Just air tested a 5x10 coil from a G2 on the F75LTD...testing a Buffalo nickel.... settings sen-70 disc-0 mode-BP tone-3H... clear repeat signal at 12"...intermittent at 13".
A new 5x10 coil for the F75LTD ....testing a Buffalo nickel....settings sen-70 disc-0 mode-BP tone- 3H....clear repeat signal at 13.5".....intermittent at 14.5"
So in my case the Fisher 5x10 coil seems to have better depth when tested on the F75 LTD.

Whimpster, thanks for that...still interesting that it works as well as it does..

deathray Wrote:
-------------------------------------------------------
> Troy needs to get back in the game.


i like troy! spoke to him at length back in the late 90's
dedicated relic hunter,and full of sound ideas!..maybe he will
jump back in the game!..takes a "ton" of scratch these days though!
hope he does!..i'm just sayin'

(h.h.!)
j.t.

DJK Wrote:
-------------------------------------------------------
> I've been around a long time, just don't post very
> often. In the days before the internet, I bought
> the Fisher 1260, new, through a detector magazine
> ad. Years later, I bought the CZ6 when it first
> came out. Later, the F75 came out, I just had to
> have one and it was a disappointing experience. I
> don't think anyone knew if theirs was "correct" or
> not. Back then Fisher had a $50 upgrade offer. The
> $50 fee for corrections, got me a new battery door
> gasket and whatever else they did, I don't
> remember. But, what really got me was during the
> $50 visit, the detector was returned with a new
> coil and a letter from Fisher stating they
> replaced the coil as it was tested, requiring a no
> charge replacement. Old coil, new coil, I noticed
> no change in how the detector operated after the
> Fisher fix. So, just like mine, there are a lot
> of F75 users out there that wonder/wondered if
> they really know or knew if their detector
> functioned properly. Tom's certification is
> great for the guy who wants to hang in there, I
> chose not to. I may or may not buy another
> Fisher, likely not for some time, this fix still
> doesn't seem to be corrected to everyones
> satisfaction.
> It is sad to think about new or used F75 buyers
> who don't follow the forums, those who don't know
> about all these issues. What F75, in need of what
> fix are you buying if you bought one today? I'll
> bet all dealers are itching to rid themselves of
> current inventory.


if it was me,i would not hesitate to send the 75 to tom,and let him do
his thing!..once certified/validated,i would have peace of mind going forward
that my $1.000.00 instrument was "right" "out the door" from fisher.

(h.h.!)
j.t.

Whimpster, you compared two 'like' coils on the identical detector? Are these coils designed to be identical?

go-rebels Wrote:
-------------------------------------------------------
> Whimpster, you compared two 'like' coils on the
> identical detector? Are these coils designed to
> be identical?

go-rebels....the coils are identical looking in size 5x10.... one is designed to work on the G2,Omega,Gold Bug, or GB pro, G2+ and a few of the frat brother detectors.
The other coil is the newest 5x10 coil from Fisher... designed for the F70 and F75.
Yes both coils were tested on the same F75LTD....I found the coil designed for the F70/F75 to gave a bit more depth in a air test.



Edited 1 time(s). Last edit at 01/29/2015 10:34PM by Whimpster.

Whimpster Wrote:
-------------------------------------------------------
> go-rebels Wrote:
> --------------------------------------------------
> -----
> > Whimpster, you compared two 'like' coils on the
> > identical detector? Are these coils designed
> to
> > be identical?
>
> go-rebels....the coils are identical looking in
> size 5x10.... one is designed to work on the
> G2,Omega,Gold Bug, or GB pro, G2+ and a few of the
> frat brother detectors.
> The other coil is the newest 5x10 coil from
> Fisher... designed for the F70 and F75.
> Yes both coils were tested on the same F75LTD....I
> found the coil designed for the F70/F75 to gave a
> bit more depth in a air test.

If I decide to buy an F75 in the future it's nice to know that the 5x10 from my G2 will work on it also at near 100% performance. that would be about a $200cdn savings up here....

Hi,,,,,hey you guys that are interchanging these coils,,have you ever checked to see if the VDI numbers were correct?..Also did these coil mess up their discrimination capabilities or change them????....JJ

NASA-Tom Wrote:
-------------------------------------------------------
> The F75 is a microprocessor driven platform;
> subsequently, nothing to adjust. This leads to a
> 'go / no-go' scenario.
>
> Bryanna = True words. And I'm certain the design
> engineers cringe when their original design
> blueprint/intent ..... is sent to the
> manufacturing & assembly line ........ of
> which/then, ends up being built incorrectly.......
> then ends up having errors in the final product.
> Makes the engineers look bad...............
> when............ in actuality............... the
> error had nothing to do with the original
> design/intent.

I know they are Microprocessor based but there shoud be some form of software driven calibration/adjustment. Also the RF side will always be analog but that section is engineered to be in tune - then you give the analog data to a A to D converter so Software side can kick in. In the old days the oscillators where not that good and you need to adjust then and the tuned circuits in RF needed tweaked by usually adjusting the resistor in the tank circuit. Lots to adjust but also lots to come out of adjustment.

Bryanna - Nebraska

Current - New to me but not new MXT Pro and T2 SE2 - Previous Minelab Sovereign GT, Minelab Safari, Whites DFX, Whites Eagle Spectrum
Smile its a good for you!

huh?..what she say?
i been schooled!..ehe! he! he!

(h.h.!)
j.t.

Bryannagirl wrote:

"I know they are Microprocessor based but there shoud be some form of software driven calibration/adjustment. Also the RF side will always be analog but that section is engineered to be in tune - then you give the analog data to a A to D converter so Software side can kick in. In the old days the oscillators where not that good and you need to adjust then and the tuned circuits in RF needed tweaked by usually adjusting the resistor in the tank circuit. Lots to adjust but also lots to come out of adjustment."


seems to me that if they need to go through that process the detectors would better match each other in performance. also, to keep the costs very low on the cheaper digital detectors (the vast volume of their business) they could not afford to 'tune' them. so, at least for these cheaper units, they would need to be designed to work 'as assembled', i.e. QA would simply be 'does it turn On/Off'......maybe Tom could venture a scenario for the calibration/testing cycle on the higher end digital detectors....

The only adjustments inside the F75 / T2 control box are Fine & coarse master Ground Balance. If these were a bit 'out' you may see target ID numbers vary, that's it. In principle, it would be possible to program each micro uniquely, eg. with calibration data that reflects the performance of the hardware in that unit, but I don't believe this is done. Coils can be re-tweaked, there's been a few threads on here where folks have had coils back from FT and the rear cover has been removed/re-glued. But that's a factory job, unless you're an expert....

thanks for that Pimento, it's an interesting topic...

Given the electronic architecture of the platform, wouldn't a single air test in a low EMI environment and another air test in a medium, AND CONSTANT, EMI environment be sufficient?

I think that the biggest variable isn't so much the software issues, but component tolerances. The tighter the tolerances, the more uniform the product, BUT the more expensive it is as well. That's probably the biggest reason why (even with analog machines), one unit will be hotter than another, even off the same line the same day. One machine might by the luck of the draw have most components smack in the middle of the design tolerances, while the next might still in in tolerance, but right at the edge on one or more components. It might pass muster but not have the same performance as machine #1. Its simply the nature of the beast. If we want better more alike units it follows that we will have to pay a lot more for that.




canslawhero Wrote:
-------------------------------------------------------
> Bryannagirl wrote:
>
> "I know they are Microprocessor based but there
> shoud be some form of software driven
> calibration/adjustment. Also the RF side will
> always be analog but that section is engineered to
> be in tune - then you give the analog data to a A
> to D converter so Software side can kick in. In
> the old days the oscillators where not that good
> and you need to adjust then and the tuned circuits
> in RF needed tweaked by usually adjusting the
> resistor in the tank circuit. Lots to adjust but
> also lots to come out of adjustment."
>
>
> seems to me that if they need to go through that
> process the detectors would better match each
> other in performance. also, to keep the costs very
> low on the cheaper digital detectors (the vast
> volume of their business) they could not afford to
> 'tune' them. so, at least for these cheaper units,
> they would need to be designed to work 'as
> assembled', i.e. QA would simply be 'does it turn
> On/Off'......maybe Tom could venture a scenario
> for the calibration/testing cycle on the higher
> end digital detectors....

What does 11/14 mean and how can you tell?

Bill

Yep - component tolerance is huge but more a factor on Analog side then digital.

Bryanna - Nebraska

Current - New to me but not new MXT Pro and T2 SE2 - Previous Minelab Sovereign GT, Minelab Safari, Whites DFX, Whites Eagle Spectrum
Smile its a good for you!

Hello
Please for info Magnum Force 25 6,59 kHz.
Regards