F75LTD2 Target Audio Fade

[berryman]

I have a brand new F75LTD2 (11/14). When I put my coil over a target, the response is usually clear, bright and loud. However, lately the target response periodically fades to the point that It's barely audible. I can usually remedy this temporarily by turning up the volume knob. However, after several minutes the problem repeats.

I used to think I was bumping the audio knob out of adjustment. However, careful attention to that possibility has convinced me that's not the case. It almost sounds like there's a loose wire some place that might be causing the audio fade. However, the cable connections at both the housing and at the coil appear to be nice and secure. The earphone cable seems OK, but I have no way of knowing what might be going on inside the control housing or inside the coil.

Have any of you experienced this problem? If so, do you gave any recommendations?

 

[mudpuppy]

Great post! You did a good job with the info provided...I'm guessing your rig is too new for it to be a sloppy cable jack connection, (a problem I have from years of use) On every hunt, I turn my rig up to full volume, and adjust my phones to balance the tones accordingly...thats really what you should be doing, run it full on power to your phones, and then dial down and balance the tones at the phones...(not like you are doing)

Doing this, most of the time all is well, but there are some days when the audio fades, muffled, or is not balanced, and for me it has to do with the ambient barometric pressure and its effect on my ears, or the jack...so I pinch my nose and do a pressure ear clear like a diver does, or I pull the jack and lick it and stuff it back in...and that seems to solve it.....(I have very bad ears, and a very sloppy female phone jack)....

The main thing I like about the F 75/70 is the proportional audio regarding a targets depth...a softer sound as its depth in the dirt increases...

I guess if you have good ears, have a look at your phones..And always run your 'power on switch' (pot) to full power...I bet thats it...

I am assuming since you have a top shelf rig, you have a quality pair of stereo phones w/adjustable independent headset volume knobs?

Sporadic problems with any gear are hard to troubleshoot, what headsets are you running?.

Hearing trouble can really sneak up on a guy...fast...somebody will be along to add to this advice if you can let us know what phones you are using....I suspect its in your phones or in your head...you can always try another set of phones..and I really hope thats what it is....its pretty hard to try another head....A guy with good ears can do this Sport blind, but once your ears take a dump...things can get frustrating..
Mud

 

[foreign object]

I have. Sort of like the target is trying to track out. I can move the coil off to the side and work it a couple of swings and then move back to the target and it will hit it hard again.
Haven't got to spend much time with the new f75 yet so I have not really tried to see what it is actually doing.

 

[berryman]

Thanks Mud: I'm using Killer B Wasp headphones. I don't seem to have a problem with these headphones on any of my other ridges (e.g., F19, MX5, M6, Eldorado, etc.). I did notice this morning that I was having occasional EMI problems (near railroad tracks). I also noticed that I have the same intermittent audio problem with the F75 that I have with most of my other detectors - that is, when I bounce my coil or accidentally hit it on something, the audio will sound off momentarily.

 

[ez4sure]

that does sound like a internal problem, have you tried a diff coil ? my updated 75 has worked perfect so far sounds like yours needs a trip back to the factory gl

 

[mudpuppy]

Ok..good stuff Berryman,..lets rule out any mechanical problem with the phones...how about swing speed? This may also apply to foreign object's input...I do know the F's like a really fast swing speed...they will ping on a target when swung fast, but not so much when swung over it slow..but then again you have a 19, so its probably not that....

You are doing good dilligence here, trying any and all scenarios to figure out if its a machine/gear problem, or 'operator inconsistencies' before going into full on 'send it back' mode ..one thing, a guy HAS to trust their gear, this Sport is tough enough without wondering if they have a mechanical/electrical gremlin aboard...Anybody else out there know what this could be?
Mud

 

[detectingMO]

do you also have the MaMa bug in poinpoint 2l and 2h tones?

 

[WV62]

I don't have a clue, but it sounds like for the most part you are on the right track. If the problem is consistent enough I would try to hunt without the headphones and see if it does it with the on board speaker.

I would try a different coil.

Check your batteries you may have a bad one mixed in with good ones, I had that happen one time but I don't remember what the detectors reaction was. I know it didn't give me a low battery alert like you would think it would.

Once you get down to the detector and still have the problem it is time to send it back for repairs.

Ron in WV

 

[basstrackerman]

Yes if you have moma bug then send it back.. I seem to remember mine doing something similar to what yours is doing

 

[squirrel1]

I will say most times times when coils are a problem, once they go they're gone, meaning good/correct performance will not mysteriously return. You never mentioned which tone used ?? Is it all? And have you tried another coil say the 5 inch??? Does it do it in both 9.0 and 9.1??? And yes does it do it using external speaker??

 

[jas415]

If you wrap a rubber band behind the on/off knob it will create a tiny bit of friction and make the knob less easily moved. Also, my granddad showed me that when putting a 2-piece rod together for fishing he would rub the insert end of the rod, similar to the headphone jack, along the side of his nose and the oil on the nose skin would then be on the ferrule and keep it from sticking. I do the same on the headphone jack. Keeps it minimally lubed.

On my 75, I know that if I have the on/off knob turned all the way up, and it hits a good shallow signal, the target signal and the 'overload' signal will drop in half volume if I get directly over the signal. I figured that was some sort of 'safety' feature.

 

[mudpuppy]

Jas415! You are the MAN !

That 'Nose grease' fishing pole trick is exactly what my Grandfather showed me back 40yrs ago!. And what I use to this day, on rods, knife blades, or that phone jack, any small item that needs a lube.....

I didnt think anybody would get it, so I didnt throw it out there as a post for fear of being labeled a bullcrapper of monumental proportions, (which I probably am, and all here generally forgive me for).......glad you posted that!, on account of that 'Nose grease' works, and its free! Thanks for that memory Jas415!

Great!

 

[Charlie P. (NY)]

Ok..good stuff Berryman,..lets rule out any mechanical problem with the phones...how about swing speed? This may also apply to foreign object's input...I do know the F's like a really fast swing speed...they will ping on a target when swung fast, but not so much when swung over it slow..but then again you have a 19, so its probably not that....

My initial thought was swing speed as well. The F-75 hits deeper with a fast swing rather than a slow one (except in Cache or static). There also is a tendency with detectors that do some self ground balancing that if you repeatedly swing a target identically in a narrow arc the detector "learns" that bit of soil and begins to accept it as normal. Don't know if the F-75 does this. It WILL desensitize the pinpoint if you pull the trigger with the target under the edge of the coil - and this is useful for more precise pinpointing.

Try your machine in static all-metal mode. If you park over the object does it fade?

You state it beeps when bumped. That could be a problem. Could also be a loose coil cable moves through the field (they are metal too and the coil's field extends up as far as it does down). A short in the coil may cause the "microphonic" beep but would be a separate problem from a fading target.

I think it may be that an initial swing is wide and fast and as you stop to investigate they become slower and tighter - that's just natural behavior. Keep them fast, low and level and two feet wide and "X" the target.

 

[Charlie P. (NY)]

Jas415! You are the MAN !

That 'Nose grease' fishing pole trick is exactly what my Grandfather showed me back 40yrs ago!. And what I use to this day, on rods, knife blades, or that phone jack, any small item that needs a lube.....

I didnt think anybody would get it, so I didnt throw it out there as a post for fear of being labeled a bullcrapper of monumental proportions, (which I probably am, and all here generally forgive me for).......glad you posted that!, on account of that 'Nose grease' works, and its free! Thanks for that memory Jas415!

Great!

Used to use the same trick to get a good seal on glass pipettes. I bet that doesn't fly in a lab anymore. ;-)

 

[Tom Slick]

Is it possible that you're detuning the detector by releasing the pinpoint trigger and pulling it again while over or near the target? Just a thought.

 

[berryman]

Good thought but I haven't been using the pinpoint function.

 

[Tom Slick]

I'm sure it's operator error.