What do you mean by 'sparking to earth' ? If the earth contacts were properly made you wouldn't expect to see sparking but you might have too much current, in which case something in the path and probably on a PCB would get hot and possibly burn out.
Is this high voltage sparking or low voltage sparking?
Usually, inverters have a signal earth which is not connected to the chassis but there are a couple of capacitors connected in series across the mains input and the DC output and the connection between the capacitors goes to earth. I'd check those. They are mainly there to suppress electrical noise and help filter out mains spikes.
I agree with what mike 109444 says. You have to go back and look for solder splashes, bits of swarf, dry joints and so on and make sure the connections are firm and correctly placed.
These people do circuit boards for £50-£60 a time, probably plus import duty
http://www.river-weld.com/index.php..._description=1&categories_id=1819&keyword=wse
LTS might be the safer bet.
But if you are not confident that a simple board replacement is going to fix the problem, trying new boards at £50 a time is an expensive option. You'd have to be sure that any board was for your model and it appears that there are a lot of similar welders on the market made by different companies. You'd have to be sure there wasn't another fault which would blow up the new board straight away.
As I said before, working on something like this without a circuit diagram is working blind. Worth having a go if the other option is to throw it away and very often it can be a simple fault, like a loose connection or burned component which can be replaced, but there's a fair chance it won't be so simple.
Is this high voltage sparking or low voltage sparking?
Usually, inverters have a signal earth which is not connected to the chassis but there are a couple of capacitors connected in series across the mains input and the DC output and the connection between the capacitors goes to earth. I'd check those. They are mainly there to suppress electrical noise and help filter out mains spikes.
I agree with what mike 109444 says. You have to go back and look for solder splashes, bits of swarf, dry joints and so on and make sure the connections are firm and correctly placed.
These people do circuit boards for £50-£60 a time, probably plus import duty
http://www.river-weld.com/index.php..._description=1&categories_id=1819&keyword=wse
LTS might be the safer bet.
But if you are not confident that a simple board replacement is going to fix the problem, trying new boards at £50 a time is an expensive option. You'd have to be sure that any board was for your model and it appears that there are a lot of similar welders on the market made by different companies. You'd have to be sure there wasn't another fault which would blow up the new board straight away.
As I said before, working on something like this without a circuit diagram is working blind. Worth having a go if the other option is to throw it away and very often it can be a simple fault, like a loose connection or burned component which can be replaced, but there's a fair chance it won't be so simple.
