[TheForge] More Tig questions.

[Ralph Sproul]

Ben,  The contact points your mentioning would be the High Freq. points.  I
usually use a piece of fine grit paper(400-600) to clean them and setting
them close to the .008 gets less resistance for starting than a .015 gap
will yield.

When you have this added resistance in the old Miller Dial Arc HF's, the
power draw is great and can rob other accessories on the machine(gas
solenoid?).  Maybe setting the gap and cleaning the surface for a better
start will free up power to make the gas solenoid work better.  If not, the
gas solenoid is not opening.........there were machines with "gas pre and
post flows" as options on those machines...........is one of your gas flow
dials set incorrectly?  This might also help your situation.

Often on those old machines the starting capacitors are weak (if they are
drooling black tarry goo down the front of the panel).......that is
definitely the case.  Use caution in dealing with these if you mess with
them..........they hold a serious charge and can give you quite a high
voltage shock.  I always wear heavy gloves and ground the parts out to the
chassis to discharge them with a jumper wire before servicing. If the
cleaning and resetting of the points makes it work.........don't mess with
the discharge capacitors! - those are the last resort to making that machine
start and work better.

Also if this machine is in a high dust/grinding area.........disconnecting
the power, and cleaning all the dust off the components certainly aids in
starting an old High Freq unit. But you seem to be indicating your gas is
not flowing .......more than the arc is not starting??  Those points should
not affect the gas flow unless it is a severe power draw robing the machine
of what's necessary........that's rare and is often from running to small a
power pigtail to the machine more than the points out of adjustment.

Most times on gas flow it will be a mud wasp nest in the lines if they were
left open and are now trying to be used........or the preflow dial is set at
0 and is not allowing a gas flow to start upon starting to weld.  The gas
solenoid could be bad (which means you could put a direct line with a valve
in it to just run it manually to get the job done).  The starting pedal also
has three tines on it for the front of the machine.........if one is not
making contact, maybe the gas solenoid is not getting power.

There's a few things to check out.  I have one of these Miller Dialarcs and
they are a bit finiky.

Ralph

----- Original Message -----
From: <Loktr at aol.com>
To: <theforge at mailman.qth.net>
Sent: Saturday, August 14, 2004 7:22 PM
Subject: [TheForge] More Tig questions.


> Well after i posted the question about gas porosity i wnt back to weld
> somemore and maybe i found the problem.  When I depressed the pedal the
arc acted
> totally sporadically and I got a big porus spot.  I checked and my gas was
not
> flowing and there was a arcing noise.  This is a Miller Dialarc HF and it
has a
> set of what look to be contactors.  They say set at .008 check manual
(which
> I do not have)   I checked the contactors and they were arcing and
probably
> close to .015.  Now there is no gas flow whatsoever.
>
> Can any one tell me what they do and how to adjust them?
>
> Ben
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