Each machine manufacturer uses a different power pin, which is the brass piece on the end of the gun that plugs into the welder. On some guns you can change the power pin but others you can't.
Good news is those are about the simplest welders to troubleshoot as you can find. Power switches are probably the most common failure on both. The range switch on the one on the right is also a common failure and is a little tougher to replace but parts are easy to come by.
If you are really looking for helpful advice do you honestly think that you're going to get it with an attitude like that? From the little bit of time I have spent here it's seems like most of the members are pretty willing to help but it's kind of hard to tell someone how big of a sack they are...