Roland VP-540. Replaced 2 heads (black and blue) and did the pump up because i changed dampers. Did the ink fill and couldnt get any ink to flow through the lines. Got the yellow and magenta to pull through the dampers and into the head through the pump tubes below. Seems like I can get the ink to the dampers on the blue and black but cant get the dampers to fill up or pull through the head through the pump tubes. Any tips or tricks on succeeding and pumping these things up?