Okay, apparently it was the guy who sold me the Compass detector, and we have now spoken and are going to work it out. He said he was out of town, for three days, while I was burning around the collar.
He said he bought it at a garage sale, the former owner had died, used it briefly and found a quarter, then stored it for 3 months. When he next used it, he noticed on battery check it only had voltage for two of the three position battery checks, and he naturally assumed the batterys ran down, and sold it to me on eBay.
When I got it, it did not read voltage except on position #A, and it was way below the operating voltage. On the other two positions, it never even showed any voltage whatsoever. So I pulled the three battery packs out, and discovered every battery was 1.54VDC, and the packs output average total voltage of 6.19VDC, so it should have shown up on all three positions. The meter would not center, and I could get no sound out of it, nor any showing on an iron object, and the coil connector where it connects with the detector case, was taped up, and I figured it had an intermittent signal at one time, and most likely and broken power wire had shorted against the metal shield, and damaged the mother board. It was a natural assumption from my experience with electronics. But cleaning and wire brushing with a small brass wire brush, I managed to get power showing on the battery test, but still the unit would not run.
So I am assuming now, with what the seller told me, that the problem more likely lies in the power supply board, either a cold solder joint, or bad contact somewhere, maybe even in a switch. The fine tuning pot definitely is bad, rotates around and around and around. So will wait until I can get some more time, and after I get my computer that keeps crashing fixed, then turn my attention to the defective metal detector again...
so after speaking to the seller, I tend to believe his story, and just let my anger take me away, and I give this seller an heart felt apology. I will try and fix the metal detector if I can, if not, it is a parts machine....Hard to find Compass parts anymore.