Oh, this is a tough question!! There are 4 locations on a heatsink, probably for IGBTs, and the other 3 locations may be diodes.
Operator manual with block diagrams:
View and Download Lincoln Electric V160-S service manual online. V160-S welding system pdf manual download. Also for: V160-t, 10877, 10878, 11031, 11032.
www.manualslib.com
Perhaps someone on this Forum has the same machine, and can open it and identify the components for you.