Used SumUp 3G+ card reader with original charging dock. Actually barely used the dock and only lightly used the reader but have had for some time and expect now out of warranty. The reader powers on when plugged in, but switches off when unplugged, so at a guess the internal battery needs replacing. It also does not charge via the dock, just when plugged in directly. It hasn't been opened or tampered with – ideal for someone with the know-how to repair it or reuse the parts. Sold as-is for parts or repair, no returns.
eBay