So it sounds like you’ve got it all worked out but please give more info about your diode. The guide was written specifically for the2.8w ndb7875 diode. If you have a 2 watt diode then you’re likely driving it too hard at 1.6 amps. It’s probably an m140 diode right? If it is then you should set current to about 1.2 amps instead of1.6. Most 2 watt diodes are rated for 1.7amps MAX. It will degrade quickly at your current setting.if you’re running a2.8w diode then disregard this.