Gb pro dd coiltek

Hopefully some one can help me recently purchased a old style coiltek dd pro 14 for my sd 2100 some how it doesnt seem to be any sound on ch 1 an ch 2 very hard to gb I read something about these older coils an something to do with the colour of the circuit board that can cause this

sounds strange. I have an SD2100 but am not an expert on it.
I have 3 old terracotta coils with mine & they all work fine, tho I don't know what colour my circuit board is ... never had it open!
17x11 Coiltek Pro Gold Hunting
18 Coiltek GP All Terrain
18 Coiltek Super Detector
ground balances fine
If theres a problem with your detector it might be worth getting it looked at.
One place I do know that can service/repair/modify these old detectors is https://detectormods.com/forum/

The circuit board should not make any difference ,just try another dd coil if it OK then I would say its the coil if it is the same then try the battery cable just to pin point the trouble ,if its in the control box you may have to get it looked at but where to go that's the problem regards john