These are the bad thing with it is no book on the circuit's, these use a surface mounted components so we dont know what they are, but if we knew what everything is . I would thing if Troy is still around he might have the info you need.
Another thing is you see any place on the case that shows it may been dropped and the board my have also have a crack in it that can be repaired. It would be nice to see what happened when he didn't use it anymore and if it does anything at all, if not is the voltage getting to the circuit board meaning the battery connection are good as I believe it uses drop in battery and those connection with the wire that goes to the circuit board.
I sure hope it is something simple you can figure out if it is totally dead.
I have a X5 also with 2 coils that I love and have done well for me, but don't use it much anymore because of health issues. Used to be able to go behind many other high price detector and show what they miss as the go so fast as the response was fast with X5.
Good luck and hope some of the info helps.
Rick
I’m so glad you understand how old is metal tactor works or how important it is to meet you because he’s gone three he gave it to me in working in order and I messed up soldering on a speaker connector and then because my soldering iron was too close to where the soldering it burnt out a couple of resistors there at least they popped loose and I can’t get them back down without trying to destroy the board and I want I did that I was like I don’t know what I’m doing at this point I’d rather have someone else try to fix it so luckily none of the marking marked out ones are missing they’re all there the only thing I’m really missing is the or blue square boxes I forget what they’re called