I'll quote from Cozza on the old board talking about a similar problem, as I don't know if he's re-registered here:
"Sounds like you need to replace the two SMD electros shown in this picture. Make sure that you clean the circuit board thoroughly with Isopropyl alcohol, as they have likely leaked electrolyte on the circuit. I have had to do this to both my beolink 7000s, and it fixed them both of the "no contact" symptom.
22 microfarad, 6.3 volts. Higher voltage may be used, provided the physical dimensions are similar. 4mm diameter, 6mm height."