ShopMaster 300 not working correctly

[Rlrsk8r]

It's been a couple years since I did any aluminum but I went to the shop to do an aluminum tig job (simple inside corner) on the Miller Shopmaster 300. It has a MIG feeder and a TIG HF unit (and I could hear the HF) on it. Has a bottle of Argon that was running about 50CFH. I verified gas coming out of the TIG torch and reduced it to around 20 before I struck an arc.
The shop owner told me that about a year ago the capacitors blew and he sent it out for repair. The LWS sent it to W Va (Miller repair depot) for repair and it worked when it came back. Then later on, it simply stopped welding and he hasn't been able to get it to work at all.
I tried it and the tungsten was sharp and all work was clean.
I set the amperage at about 100 amps AC and attempted to strike an arc but only got a rough arc. I was finally able to get a puddle but the arc was still EXTREMELY rough and unstabe like it had no gas. The tungsten melted and the cup got red hot and cracked.
I was at no time able to make a good puddle as I've done with other welders and what little I was able to do was simply CHEWING GUM.
Does anybody have suggestions ?

[cruizer]

You say that you can hear the HF, can you see it off the end of the torch?? Maybe your torch is not hooked up right in the HF box.

[Rlrsk8r]

You say that you can hear the HF, can you see it off the end of the torch?? Maybe your torch is not hooked up right in the HF box.

Shop owner said it was working previously and he's changed nothing. I have to go with that.

[cruizer]

Well, just cause something worked laaaassst time, doesn't mean it worked correctly. So if it worked last time the problem must be with the operator certainly NOT with the machine or hookups.

[ccawgc]

Try stick welding in both AC and DC. If good, the look at your HF box .
Down load the operators manual from this web site and make sure it is connected correctly. If all good the pull the cover off the HF points and look at them.
The arc should be crackling and not a soft buzz. Also see if the points are 1/2 inch or 1/4 inch dia. The 1/4 inch sized points holder has a bad habit of failing.
Miller has a kit to put the 1/2 inch size ones in. If you have the 1/2 in size they made need to be replaced if they a pitted or very dirty.

[RoGrrr]

I went back to the shop and removed all the accessories so I could verify the power supply. I set it up for stick with 6013 and was able to lay a smooth bead with it.
I then attached the tig torch and HF unit and opened the gas bottle (Argon). Again, I verified gas flow and post flow with the torch pointed into my ear. Yes, I turned the HF off before I did this.
I tried to lay a bead on SS. The arc was ROUGH and noisy, almost like the a wrong gas bottle was hooked up to the manifold but this time the only bottle hooked up was ARGON. I never was able to get it to form a decent puddle. I tried AC and DC/both polarities.
The stainless was .050 and the tungsten was .065. Every time, the tungsten melted and the base metal burned thru.
I varied the current all over the place, changed the HF settings too.
I took the side covers off the power supply to visually check and the main switch was in good shape, with all the sections operating normally/properly.
I also checked the circuit board visually and found no evidence of a bad connector or burned component on the board.
At this point, I'm at a total loss as to WTF is wrong.

[cruizer]

OK, for steel gas must be 20 CFH Argon is ok

Straight polarity in tig (neg to torch pos to ground clamp)

HF in start

Now its not nessessary to even use the HF starter in Steel, just scratch start to the work piece off a piece of scrap

For Aluminum

AC only

HF in continuous

[RoGrrr]

OK, for steel gas must be 20 CFH Argon is ok
Straight polarity in tig (neg to torch pos to ground clamp)
HF in start
Now its not nessessary to even use the HF starter in Steel, just scratch start to the work piece off a piece of scrap
For Aluminum
AC only
HF in continuous

Cruizer
I did all that. NO GO. I tried HF in continuous. NO GO. I tried all polarities. NOTHING WORKED. I had HF. I could hear it. I could feel it. It also darkened my hood.

As that OLD commercial used to say: "WHAT'S A MOTHER TO DO?"
Oops. I'm dating myself....

[cruizer]

Did you try scratch starting direct off the machine? (shopmaster)

[RoGrrr]

Did you try scratch starting direct off the machine? (shopmaster)

Yuuuuup. The problem is the ROUGH ARC when I get it to glow. Even when I was a newbie, I NEVER had an arc like that. Something's fubar'd.
That's my story and I'm stickin to it