@Peter T you’re question about the wire is a good one but you didn’t supply info to help us answer. How long and what gauge wire are you using? Very strange to get two bad drivers. If you’re sure that everything has been done correctly you can try repeating process with voltage set to 5.5 instead of 6.5 volts. Maybe that will let you raise current higher. The laser will operate well at either voltage setting so long as the current doesn’t exceed limits.keep us posted.