That is good. It means we have AC mains, there's no blown fuse, the auxiliary transformer primary is OK, and the secondary output voltages are correct. ( I don't know why it needs all those outputs, most auxiliary power supplies are a straight single 24v.... )On checking the wires you described there is 26v , 18.6v , 18.6v , 26v.
The Tec-Arc photo is of the older type of pcb, with 'thru-board' components, not smd. See what they say.
A replacement from Sealey is £82 plus vat, so it's not that much more.