I thought it was worthwile posting it as it does show some of the
details of the power side, if not the control system. It was mentioned
earlier in the thread that no schematics had been found so it may be of
some use. The welder is definitely AC and DC, if the schematic can't do
that then I guess the manual is wrong, but it is entitled "power
transistor controlled, AC/DC TIG arc welding power source".

Jon Elson wrote:

David Billington wrote:

I have just scanned the schematic for a Hitachi inverter TIG and
added it to the dropbox.
The jpg is about 1mb.

http://metalworking.com/DropBox/HitachiInvTIG.jpg
http://metalworking.com/DropBox/HitachiInvTIG.txt

This isn't much of a schematic. All the circuit boards
are just rectangles. Also, this is a DC only welder.

Jon