I have had similar problems with both my PTP 1 machines, and one of them cuts out after a few minutes when it is being played on the mains. I too bought new batteries, but these didn't seem to help. I have got round this by forgetting about the power supply and I now charge always from the U S B and always use the unit on batteries. I have now purchased the Lineo, which is useful for if I want to do any mains recordings. Peter