My headphones wont work with my roland keyboard

I wonder why the ribbon cables have been replaced as they do not fail.
Check the keys actuate the contacts properly.

Open up the Roland E-80 and check if all connectors and flatcables are well seated.

How can you state power supply is working excellent, please?

search google for "JX-1 FACTORY RESET". If that does not help, try your headphones. If that neither, you blew the Audio Power Amp circuit. Take it to a Tech. Good luck !!

Open up the Roland G-70 and check if all the connectors and flatcables are well seated. Check also if the power supply is working as supposed to.

You left off the one bit of info we need... however, make sure the volume control on the keyboard is around the halfway point... If it is way down, turn it up and reduce the channel volume knob some. Make sure the cable from the keyboard is an instrument rated interconnect and not one intended for speaker (usually marked as such). Make sure the keyboard AND this amp are powered from the SAME receptacle... even if you have to run an extension cord. Listen with headphones on your keyboard to make sure the sound is clean there.

I have two Yamaha's and I will say they are maintainable. Almost ALL the weighted piano key models use a keyboard made by one company as I understand it. I can easily get service manuals for the Yamaha, not quite as easy for the Roland... same goes for repair parts. Your decision... listen to each and decide. Hint: Use a set of headphones to do the compparision rather than internal speakers as the orientation in a music store can drastically change the sound.

Check if headphone output is normal... sometimes the headphone jack switch fails and doesn't send to speakers when headphones are unplugged.

Make sure that the level of the headphone out put is open. Make sure it is on manual adjustment and no auto level. And test your headphone on a other device to clear that your headphone is not broken. If all these options are correct you headphone pre amp of the XP 50 may be damaged or broken.

Try Roland.com on the internet. It's a pretty good website and should show you dealers in your area.