These UHF portable radio sets are good value, but the supplied mains chargers aren’t the safest design (and also cook the accus if they are left on charge constantly).
you can buy better 6 unit chargers from HongKong, but in the meantime I investigated and modified one of those I already have to make it slightly safer – which was a fiddly and awkard job due to its construction. I would not suggest doing this unless you are confident with working on mains voltage circuits!
At least it all worked when I put it back together, the mains circuitbreaker didn’t open nor did I take a hit off strong voltage and the output voltage is correct raaa. I made a couple of slides showing how it all fits together (and an overview of how these power supplies work – many mobile phone and USB chargers use similar circuits)