Can anyone with a sync 200 try this & see if the welder makes a hissing noise.

Set welder for about 100 amps, press peddle fully & see if machine makes a hissing noise ?

Was trying to find reason for porosity all of a sudden.

Was adjusting gas flow & noticed this hissing noise, thought may be a leaking hose, so took side cover off.
Hose is fine, noise that sounds like a leak is coming from the center area of machine.

This may be a normal noise , but just was not noticed before.

Welder worked fine a couple days before, now all welds are full of porosity.
Still have 500psi of gas ?

Just dont know what problem is.