Suddenly, my battery lost its capacity – it was enough for only 6 hours at TX=1.
Came a guess: couldn’t a strong neodymium magnet for treasure searching, which I was carrying in the trunk of my car in a bunch of different search equipment to be near the coil and have any negative impact on it?
(I will say that I still use old type of black coils, not X35 XP Deus coils).
To clear my conscience, I take a magnet of 80 kg (40 mm in diameter) and walk around those place where the coil contains the circuit board with an LED.
After that the frequencies on the board are switched with a delay, and the coil except for 18 frequency does not generate anything (ie, works only at 18 frequency).
Having studied all available information and datashits of XP Deus coils, I understood that there are polarized relays with their magnet inside. By the way, it is thanks to them you can hear light clicks when switching on the metal detector or when you switch from another search program.
Axicom IM41 3vDC relays. Also suitbale: Omron G6K 3vDC, IM41 3V
under SMD mounting the feet are bent outwards.
After resoldering and repair the XP Deus coil the relay all worked.
So be wary of search magnets, or at least do not carry all equipment in one pile when the coil and magnet may be in close proximity.
I have never encountered such damage to a coil before. Usually, micro cracks can sometimes appear from merciless operation and then moisture can penetrate into the coil.
In this case the coil starts to squeak randomly. You can notice such a breakage by the presence of condensation droplets under the plastic cap of the LED on the coil.