Were they new heads and dampers? As the problem, at least from what I've experienced and heard of, is that when you remove the dampers, if they are still full, the ink leaks out into the inside of the head and fries it. The only way I've successfully re-used a head, is by emptying out the lines so that there is barely anything left in the dampers, flipping it upside down and removing the dampers and installing new ones. My recommendation would be to inspect the heads you are trying to see if there is any ink that leaked, and if so, then it is pretty much guaranteed that head is n
