I bought a used 8inch minelab coil for the quattro but think its bad any ideas?

[Trackerman]

Well i bought a used 8inch coil for the quattro but i think its bad. Because on a penny it was reading in the silver range? When usaly with my larger stock coil pennys read at about 35 in the copper bronze range. Well coil was missing a screw at the top of the conector and was loose a bit at the bottom and i hand tighend it. Any way i got a refund and am sending it back to the guy.Dont like stuff when its iffy. Any ideas why it was reading pennys in the silver range at 37 .When stock coil reads them at 35 in the bronze copper range? In coin and jewlry mode with sensitivity set to auto.

 

[John (Australia)]

I have dug targets that are a number or 2 away from what I would usually expect and if a noise cancel doesn't correct the id then I just put it down to the ground conditions in that area. You didn't state if you where digging pennys or just air testing.
John

 

[Onus]

I had a problem that copper pennies always read 37 on mine and I noticed it was reported the same on several other machines. I think all the ones I read was with the standard 11" coil, but I have a 6" that reads the same. I think it is the processor in the machine and not the coil? Onus