Is Something Wrong With My Fisher F75?

[treasurepirate1]

i went on a hunt last weekend and noticed a slight background hum from my detector (fisher f75) right when i turn the sensitivity to 88 all the way up to 99, and there's no hum when it's at 87, it doesn't seem to affect the performance because i found some great finds on that hunt. I never heard the hum before last weekend, I read similar story's on another web page with the same hum starting on 88 for multiple fisher f75s just like mine. The sound gets annoying so i'm not going past 87 sensitivity now, was the hum always there or have the electronics slightly changed over time.

 

[MKnTenn]

Mine does that, it goes away when i go to F2 on the sound. HH

 

[TerryC]

I was going to buy a F75 when they first came out. The salesperson tried to tune up under some power lines across the street (DUH!) I didn't buy that day. TTC

 

[umrgolf]

Was an F-75 user for a few years and never had much of a problem with it.. At least nothing similar. They do chatter quite a bit but setting the discrimination at 7 or 8 always worked for me I know Fisher is very good about fixing faulty units. Doesn't hurt to shoot them an email.