Karl Townsend wrote:
I picked up a millermatic 250 welder with an AL spoolgun at an auction
a while back. I tried the spoolgun a couple days ago. It works but the
feeder is stuck on "HIGH" That is it feeds the AL wire at full speed
when welding and the speed knob has no effect. It welds great if you
can use wire that fast.

I first tested the spoolgun itself
http://metalworking.com/dropbox/miller250spoolgun.pdf

The reostat is 10K ohm and the wiper goes from 0 to 10 K just fine. I
seen no obvious mechanical issues. (I was really hoping for a broken
pot, etc.) This was tested right at the plug to the welder.

I located the electrical prints for the welder
http://metalworking.com/dropbox/miller250prints.pdf

The spoolgun connection is shown right at the bottom of the print.
Before I give up and send it to the welding supply for repairs, are
there any other simple possible troubles to look for?

Karl


Didja try the gambits offered in the Owner's Manual
on page 16?
www.millerwelds.com/om/o1308n_mil.pdf

Low, high, or erratic wire speed.
Readjust front panel settings (see Section 3-1).
Place Low Range/Full Range switch in correct position (see Section 3-1).
Change to correct size drive rolls (see Section 4-5).
Readjust drive roll pressure (see Section 2-12).
Replace inlet guide, contact tip, and/or liner if necessary (see Sections 4-4, and 4-8).
Check position of input jumper links (see Section 2-9).
Have Factory Authorized Service Agent check main control board.

--Winston