Welding Tips and Tricks

Hello,

I recently picked up a Lincoln Electric Tig 175 Square wave for about 800 bucks (in Canadian Pesos). The guy who owned it before said it was all good and I ran a few quick beads with it before purchasing. However one thing slipped by me. The post flow doesn't seem to do its full "15 second" run. It seems like the gas just stops as soon as I come off the foot pedal and the line just drains of gas in about 1-3 seconds. This is leaving the tail of my welds uncovered and my tungsten as black as some politicians souls.

Any one have a clue if its a foot control issue or a solenoid that is going? If its the solenoid, has anyone else had this issue before and what was the rough cost of repair.

Sights wrote:Hello,

I recently picked up a Lincoln Electric Tig 175 Square wave for about 800 bucks (in Canadian Pesos). The guy who owned it before said it was all good and I ran a few quick beads with it before purchasing. However one thing slipped by me. The post flow doesn't seem to do its full "15 second" run. It seems like the gas just stops as soon as I come off the foot pedal and the line just drains of gas in about 1-3 seconds. This is leaving the tail of my welds uncovered and my tungsten as black as some politicians souls.

Any one have a clue if its a foot control issue or a solenoid that is going? If its the solenoid, has anyone else had this issue before and what was the rough cost of repair.

If your solenoid was bad you wouldn't get any gas at all and isn't adjustable but I have read that it self adjusts to the amount of amperage you are using. Try turning up your CFH to around 15-20 and see if there is a difference.

I was set at 150Amps and had gas set at 30cfh. The gas just stops and ball drops instantly when I take my foot off the pedal.

Could be a bad post purge timer. If it's mounted on the board then you can add a delay on break timer after the fact.

If you find that the fix is an expensive one you could add a torch with a valve and bypass the problem.

The following link has the service manual for the SQ 175. It might not be the same code number but is full of schematics, troubleshooting procedures and repair procedures. Type in the search box Lincoln welder or other descriptor. I downloaded the manual and it is clean with no virus or malware. Also has many other welder service manuals-Miller, Esab, etc.
Searched for Lincoln and found a bunch, also Miller. Clicked on one and at the bottom of the manual preview page it says download manual(takes a couple minutes for that link to come up, says processing first). Downloaded one and scanned with anti virus. Everything was clean. They are scanned factory service manuals. Troubleshooting, theory and repair sections.

http://elektrotanya.com/?q=keres