Originally Posted by
Karl Robbers
Here's another way of looking at the situation.
What is your planned usage of the machine? You will probably get away with pulling 100 odd amps without too much drama on a 15A circuit. That should allow you to weld 3mm aluminium on AC without too many issues. Make sure that the high frequency is working before investing too much time or effort. The weld that you were shown on stainless would have been done using DC and could well have been done without HF. AC requires HF to run effectively (although it will run without as I accidentally found out, albeit nowhere near as well as using HF). Any major breakdown, and I include a dead HF unit in this, will be a fatal breakdown for your old girl.
Have a play before you make too many hard and fast decisions, remembering $1200 or a bit under puts you in an Inverter based AC/DC tig that will run on your existing supply quite well, so upgrading your power supply would account for nearly 50% of that figure, while still leaving you with a very basic machine without any user friendly features and with less performance than a budget level inverter power source.