I tried the PH in my yard before I left, and it seemed stable and working good. An hour at the other field where I got the one corroded large copper, it started the weird noises at random times, and it would not respond to my aluminum shoe eyelets. If I bumped the coil flat down on the dirt, it would work again for a while.
Shaking the coil, the guts do not sound loose in there, but I also think water got in this one from the wet grass. I'll take it apart to see what's wrong.
So now all I have is the 5.5. And my E-class cointrax has dirty Menu and Enter switches, because you have to keep trying them to get them to work.
JB said he used spray contact cleaner without taking anything apart. I will buy some because all I have is spray carburetor cleaner which might ruin something. I don't want to take it apart to soak the switches upside down in alcohol like I used to do, because the wiring breaks off the board for the mode switch ...and I'm not good at soldering those
I thought about switching to a new detector with a modern sealed coil, but I've yet to hear one on youtube that does not make those awful noises like a angry monkey screaming or yelping. I can't handle that
Oh, I went to this field because I want to know when it was first used, and how much it was used. I did get two smaller flat buttons today, without backmarks, and I think that means pre-1820. The 2 buttons are the only other early finds from there, beside that copper coin