GYSmi 183 Inverter working but wont weld

[eddie49]

Any suggestions for best way to de solder this 4 prong item?

That is the bridge rectifier, which sits across the AC mains input on all inverter welders and provides the DC Bus which powers the rest of the machine. Rather than unsoldering the 4 tags, is it not enough to unscrew the centre fastener that holds the rectifier to the heatsink?
The solder nuts will be carrying high current, so I don't think that conductive epoxy will solve the problem. Instead of solid threaded nuts, perhaps you could replace them with Z-shaped links cut from sheet copper?

 

[Ubique]

I like the idea of adding some wire links, as above, they'd need to be quite big CSA to take the current.

 

[JOEPRO]

That is the bridge rectifier, which sits across the AC mains input on all inverter welders and provides the DC Bus which powers the rest of the machine. Rather than unsoldering the 4 tags, is it not enough to unscrew the centre fastener that holds the rectifier to the heatsink?
The solder nuts will be carrying high current, so I don't think that conductive epoxy will solve the problem. Instead of solid threaded nuts, perhaps you could replace them with Z-shaped links cut from sheet copper?

I took that screw out first but there is a very thin and strong glue securing the rectifier to the aluminium heat sink behind. They will not separate can't get a snap off blade behind either. So desoldering is the only way to separate the boards on this welder.

 

[JOEPRO]

I got a solder iron / sucker combined tool on amazon, it turned up today and made quick light work of finishing de soldering the board.

I then re tinned the existing pads with soldering iron and fresh solder / flux and piled some solder up on them.

Then cleaned the nuts with bench grinder, heated them up with blow lamp, dunk in flux, quick blast of heat again then set into place.

That alu heat sink is super effective. So much so it takes the heat away in seconds.

The nuts went back on a little crooked but it's OK the screws fitted and they are very firmly re affixed. I can lift up the board assembly one nut at a time.

It'll go back together by morning and test it then. Fingers crossed its working again.

 

[Ubique]

If you've took any metal off the nuts, It may be an idea to put a washer on top of them before refitting the board so they are in compression rather than tension when the top board is refitted - well done in getting this far with a 'scrap' welder

 

[JOEPRO]

It werks!!

Got it back together tonight. Can't find my welding mask but was able to tack tack tack nice lines with it for now and it's really smooth I like it.



I'll clean up the case tomorrow and that is one French made inverter welder saved from landfill. Cost about 5 hours of time and almost nothing in materials.

 

[not done it yet]

A good outcome. Well done.

 

[angellonewolf]

top job nice what a load of work comes good in the end

 

[JOEPRO]

This will be the concluding post on this little inverter welder.

I carried out a stress test of sorts on it by running 3x full 2.5mm rods one after another. It performed very nicely and the scrap box section I was welding was glowing red after. Welder cold and didn't miss a beat.

I polished up the case, put the strap through the washing machine, new rubber cable and permplug. And splashed out on a new set of leads for it from Static Arc at £21. (It didn't come with any leads)



They still make these and they retail over £200. I got this free as it was broken. For £30 ish in materials I now have a cracking little welder (welder no 5 but who's counting)

 

[Ubique]

I don't have a dedicated MMA but as a secondary function of the GYS machines I have, they are very smooth and capable stick welders, that looks a nice bit of kit, the 13A plugtop gives it some scale as to the portability.