Hello. I have a problem with my ZOOM H4 recorder. When I try to turn it on (using ZOOM adaptor) it shows the the battery is low (but batteries aren't included) and tells me to turn it off. Also, when its turned off and the adoptor is plugged in, it shows the USB menu (connect to pc, etc.) but the USB isn't plugged in. Please help!

I found that using another power supply did the trick. One theory is that your line voltage in your building varies enough to make the unit unhappy, and another power supply may give more voltage or current sufficient for power up. The Zoom power supply is only rated at 50ma, which is VERY low for a 9v supply. I suspect that under some circumstances the zoom requires more power than the Zoom power supply can give. I recommend trying at least a 300ma one. I keep power supplies plugged in at various spots in my studio area so as not to have to plug and unplug them as I move from instrument to instrument. I found that using another power supply did the trick. One theory is that your line voltage in your building varies enough to make the unit unhappy, and another power supply may give more voltage or current sufficient for power up. The Zoom power supply is only rated at 50ma, which is VERY low for a 9v supply. I suspect that under some circumstances the zoom requires more power than the Zoom power supply can give. I recommend trying at least a 300ma one. I keep power supplies plugged in at various spots in my studio area so as not to have to plug and unplug them as I move from instrument to instrument.

are the different power supplies made by different suppliers? are the different power supplies made by different suppliers?