i have connected my A 500 pro midi controller to windows 7 pc and the device manager window is refreseshing un limitedly and the midi controller connected to Port_#0009.Hub_#0001 is turning on and off continuously.I tried changing the midi controller port to be connected to other midi ports also but the issue is not solved.how can i solve this issue?
Use only a Roland adapter because all I can find out is the voltage and that's not enough information with which to buy a suitable or safe third-party adapter - - - if you feed your keyboard the wrong polarity or wrong amps it could blow the keyboard so don't risk it, buy a Roland one.
However, since you say the keyboard used to work okay from USB power until recently, well may be you are now using more USB devices than before? If you're not, then I'm doubtful an adapter would make any difference. Maybe the problem is internal within the keyboard itself?
If you're trying to power it from a USB port, that may be causing the connect/disconnect issue due to insufficient power.
If that's what is causing it you'll need to plug a 9v DC mains adaptor in to it instead - - - was it supplied with one?
actually it wasnt supplied with any 9v dc main adapter,but it worked fine without one for several months but suddenly this issue popped up.will it be okay to use any 9 volt adapter because it is mentioned near the dc in socket that dc adaptor from roland itself should be used.