I have an old 18.6V 6.5A adapter from an old HP docking station. I tried to open the adapter and saw an small pot inside it, tried turning it but the out just remained constant and there was no change. How can I change the output with minimal components. I had previously tried with an LM2596 Buck converter to step down the voltage unfortunately I accidentally shorted the leads and it blew up. So, my first option would be to get a similar buck conv with a 75W or 100W capability(around 5A) or I need to get the above mentioned fixed voltage or a variable one by adding say a pot? Also is it safe? I've seen people mentioning its dangerous trying to modify ATX PSUs.