Thanks , I appreciate all the interest in the Lincoln 185 TIG problem , 30
yrs. of HAM radio and Airplanes , I have seen a little of everything , yes
it is the $ 2.00 mechanical encoder that is giving the problem , I work part
time for a Co. that makes precision SS parts , retired several years ago
from full time aircraft welding and the little part time works well for me ,
if the welder was owned by myself I would have pulled the PC board out a
long time ago and either replaced it with a higher quality mech. encoder or
as one post mentioned , just find the 5 v. and use an optical , Co.is under
FDA and ISO and owner is pretty touchy about everything , welder is about 4
months out of warranty and looks like Lincoln will try to give us a little
break , I guess the price of the PC Board came to mind because I wonder what
some poor guy out in the field that is clueless on the electrical thing
would do if he had the same problem , a local welder repair shop said that
he could get the board and install it in our shop , Lincoln said that he is
not on there list , got to take the thing 60 miles and two trips , looks
like the small guy always gets kicked in the ass .
"Pete C." wrote in message
...
RLM wrote:

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.

You may well find someone with the ability to troubleshoot and
repair things at the component level but the management know that the
customer will complain about the cost of troubleshooting time and the
labor to replace the inexpensive component parts. The warranty will be
limited, if any, and if the failure of the one component has stressed
another component and it fails in a short time the manager eats the
warranty.
The customer looses faith in the dealer because, in his opinion, it
wasn't fixed the first time right. These are the hardest customers to
win back.

Replacing a board (card) insures the manufacturers warranty and the
manufacturer will reimburse the dealer and recall the faulty part to find
the problem and improve future models or may offer a recall on the part
if
it shows chronic failure rates and possibly replace it free.

The OP should ask if perhaps there is a recall in effect that may have
been
over looked. Poor management tend to pigeon hole information that they
don't
understand. I've known service managers that couldn't put lead in a
mechanical pencil or were amazed that it was even possible.

There are those issues as well unfortunately...