My Lincoln Square Wave 175 tig/stick machine stopped working in tig mode. Did the t/s and called Lincoln and they agreed it was the control board bad. $483 for a new board. Found a place in VA that will repair it for $230 which was okay with me. However, if it fails again, I'd like to repair it myself but would need the board schematic. I'm a retired airline avionics tech. and have more than enough test equipment to do that but Lincoln said the board schematic was proprietary. The board repair facility said since they're under contract with Lincoln for warranty repairs, they can't release the board schematic either. The Lincoln part no. for the board is G2986-1 and I was wondering if anyone had any info on where I could get a schematic for the board. Thanks for any help.