can you still get leads for these?
A quick look seems to show a quick connect but not enough detail to show
what type. Dinse are quite a common fitting IME and readily available
from good welding suppliers and ebay. Make your own leads as they're
easy to fit and I've swapped some stud panel fittings for Dinse in the
past and they were a direct swap.
------------------------------
https://dinse-us.com/wp-content/uploads/sites/2/2014/07/DINSE_Plugs_Sockets_US.pdf
Dinse plugs are cylinders of 9mm, 13mm or 15mm diameter with a bayonet
locking lug that enters a slot which pix of the 230 don't show. If you
aren't comfortable removing a connector socket you could measure the hole as
accurately as possible, or shave down a wood dowel to a jam fit that shows
the (likely discolored) contact area and take it to the dealer as a sample.
Older plug types I've seen are a taper fit and split lengthwise for a spring
fit. I had to make brass plugs to match the taper fit.
This gives the size of the lead cables. It looks like #1 for high and #2 for
the low range only, 125 Amps has been enough for me to weld 1/2" steel plate
with 1/8" electrodes.
https://www.directwire.com/resources/welding-cable-ampacity-chart/
Good luck with it, the old Sears welder I bought from a roadie for $30 had
been patched with a steel connector panel that shorted the low winding, but
not all the magic smoke escaped and I could make it work again. The other
cheap welder I bought, a 50A buzz box, I turned into a high current battery
charger.