On Fri, 02 Oct 2015 14:11:24 -0500, Jon Elson
wrote:

Garrett Fulton wrote:

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.
Miller apparently makes board-level schematics available. Lincoln,
apparently, does NOT make these available to the public. Possibly some
shops might have more detailed drawings, but all I was able to get was a
"machine wiring diagram", where all the boards are just empty squares.

If anyone does know how to get board schematics for Lincoln welders, I'd
love to hear about it. I did manage to trace down and fix a bad capacitor
on the postflow timer on mine, that was easy to trace from the time pot on
the panel. (I have a square wave TIG 300, awesome machine!)

Jon

Was the board HEAVILY coated in conformal coating? I was asked to
repair a wire feeder attached to a power suipply...humm...Lincoln
LN-25 IIRC...and it was so thick in conformal coating I couldnt do a
thing with it. Bearly recognize the components under the goop.