Need Help Roland VP 300 problem after pint head changed

Test the fuses on the main board first. One fuse protects two heads. The one protecting Y and K may be open.

 

Also might check ends of head cables to make sure you have not damaged connectors, It only takes a small amount of damage to cause problems,

 

Have you replaced the head yourself? Could it be that, after replacing, you haven't filled the head with ink? How the damper looks like, or the tubes? Are there ink in it?

 

It is better to test the fuses to see which, if any are open. Do you have a multi-meter? But regardless, it is no use replacing a fuse unless you have addressed the reason it has blown.

If you replaced the heads yourself and it is the first time you have done this, it is quite possible that you either have spilled some ink onto or into a ribbon cable connection or you have damaged a cable when inserting it into its terminal. First do as SignEx has suggested above and very carefully check every cable you removed when replacing the head. Check it for damage and for ink spillage. You need to get a good light on it and check it very carefully as damage is hard to see and can be very slight but enough to cause a problem.