Constant noise

[EtracTom-AdirondacksNY]

Mine did that once and I couldn't get it to quiet down and I eventually found I had somehow knocked the frequency number off from the original setting. Like 18 kHz is really 17.7 or something and somehow I had moved it further away from that factory setting like when you hunt with someone and your both on the same frequency and so you skew yours a bit so as not to interfere with each other. I didn't change it from 12khz to 18khz it was moved off of 12khz
There is a way you can move it up or down away from the original number a few points either direction check that out. Other suggestion was already given too high sensitivity or ground balance way off.
I have bad soil here reads high 80's so I leave my different machines on 90 all the time and don't bother to change them.

 

[Toolman0114]

Problem solved.....returned it for a full refund.

 

[jimpote03]

Sounds pretty normal to me but I never use the factory settings. I use the setting I found in Andy's book and I don't have that issue very much.