I've actually repaired two broken hammer keys on my Roland KR-575, after paying $250 (TWICE) for a repairman to come to my house and fix two other keys.
The repair I completed was about four of five years ago. I searched the internet and found great instructions to print out. Unfortunately, I can't find them again. HOWEVER, I did find this video: Roland Keyboard Repair. It shows you the hardest thing about the repair - how to take the cover(s) off to get to the keys! The video is not as detailed as the instructions I used before - but pretty good. The parts cost me about $25.
Unfortunately (for me) I have yet another key to fix now. This time I will take pictures and notes and update here with my results. It might take several weeks though (I'm trying to finish a big school project). In the mean time, try the video. I don't recommend trying super-glue like the video says, but sometimes finding parts is difficult, so I guess that might be an option if you couldn't get the parts easily. I just don't think a weight repaired with super glue will last very long.
Here are a few suggestions to find the parts you will need:
Search online for "Roland KR-575 replacement parts".
Find a Roland authorized repair shop - they will likely be willing to sell you the parts (if they have them in stock - and if they don't, they can probably order them for you.) This link helps you find the closest repair shop to the zip code you enter: Roland Support Service Repair Service Center Locator
My other advice is to keep careful track of all the different screws you take out - and away from kids, grandkids, and pets - so you can put them back in the right place after your key repair is finished. (The screws that is ;)
if your saying the power goes on/off allot then its got to be your power cord or connector in the back , these do have a hard life as these get moved around a bit , its gonna take a pro repair to replace the power connector-but you can buy new cords for them , try to wiggle it to confirm that's it , but if your display just goes on off , this is a software problem as most likely a error in reading the drive