On Tue, 25 Sep 2007 14:02:55 -0500, Pete C. wrote:
Ignoramus30458 wrote:

On Tue, 25 Sep 2007 13:45:39 -0500, Pete C. wrote:
Ignoramus30458 wrote:

On Tue, 25 Sep 2007 13:36:16 -0500, Pete C. wrote:
Ignoramus30458 wrote:

Can you clarify just what is wrong? What kind of encoder is it? Can
you replace it with a generic part?

i

I expect that there are few to no custom electronic components in any of
these machines beyond a microcontroller chip and perhaps a PAL chip.
Most of the components should be readily available from Digi-Key. I
expect the encoder in question is about $10 from Digi-Key.

When I hear "encoder", I do feel like it is probably generic. What
kind of isolation testing has the OP done so far? What makes him or
his dealer conclude that it is an encoder?

i

I found a previous thread discussing this a few months ago. In there it
is indicated as a device that looks like a pot, has three connections to
the PCB and continuous rotation. I suspect it's a $5 mechanical rotary
encoder that is quite standard, available from Digi-Key, and could be
upgraded to a more reliable optical version for a few dollars more if he
can find a 5 volt supply for the optical version.

That makes sense, but how does the OP know that it is malfunctioning?

i

The report was that the amperage set point made wild jumps when trying
to adjust, i.e. dirty mechanical encoder contact bounce. I expect either
of us could repair the machine at minimal cost in a minimal time.
Unfortunately you aren't very likely to find someone with component
level troubleshooting expertise at a welding supply shop.

I agree, then. I would definitely try to check out the encoder before
starting on the path of $950 part swapping.

i