Sip Migweld mod.

[Alan Reynolds]

Firstly, a Happy New Year to everyone.
Now to my problem. I have tried many combinations in the search box to find the motor feed modification post for the130 model but have failed miserably.
Does anyone have the link please?
it’s a cheap welder that I don’t use a lot but I found a 24 volt laptop supply and I thought I’d try and stabilise the erratic feed.

 

[skotl]

Here's a link to all my SIP mods, the first of which has a link to the wire feed mod

The mods that made my topmig 150 actually rather good

Been meaning to say thanks to the various people who have helped me convert a £50 knackered old topmig 150 to a really pretty decent welder. Here's (from memory, but with some links) the mods I've made. I would probably have spent less if I'd bought a used (or possibly new!) Clarke but I now...

www.mig-welding.co.uk

 

[skotl]

And in case you're after an in-depth explanation of what the mod is doing and how the circuit works, I did a write-up here:

SIP wire feed power mod question.

Hi everyone, You've all been so warm and welcoming since I joined yesterday that you've only got yourselves to blame for me asking stupid questions now. LOL ! Anyway, I just want to check I'm not being thick here. I understand that the point of adding a 24V PSU to cheap MIG welders is because...

www.mig-welding.co.uk

 

[Alan Reynolds]

Here's a link to all my SIP mods, the first of which has a link to the wire feed mod

The mods that made my topmig 150 actually rather good

Been meaning to say thanks to the various people who have helped me convert a £50 knackered old topmig 150 to a really pretty decent welder. Here's (from memory, but with some links) the mods I've made. I would probably have spent less if I'd bought a used (or possibly new!) Clarke but I now...

www.mig-welding.co.uk

Hi Skotl, thank you for doing that. My board is slightly different to the one in your circuit in that I don’t halve connector CN5. My board version is MIG03A IPF. Looking at your drawing, it seems CN5 is just a jumper on the board.

 

[skotl]

Hi Skotl, thank you for doing that. My board is slightly different to the one in your circuit in that I don’t halve connector CN5. My board version is MIG03A IPF. Looking at your drawing, it seems CN5 is just a jumper on the board.

From memory (and my earlier diagram):

CN5 connected DC out from the main transformer to the fourth pin on CN1 which in turn feeds some volts (let's say 20VDC) to the motor feed switch circuit, on pin 4 of CN1.

So in other words... There is a link from cn5 pin 2 to cn1 pin 4. You want to cut that link, and insert the VDC+ output from your laptop PSU to pin 4 of cn1.

If that's not making sense, please post pics of your PCB.

 

[Alan Reynolds]

Hi Skotl, thank you for the reply. I have attached a couple of pictures of my particular pcb. I think I’m ok working it out.

I’m just about to order a relay and a new 1k linear pot and possibly a multi turn one for the trimmer.
The wire feed only work when at zero or 1/8. Otherwise it fed through wire like a lunatic.
I don’t do that much welding but it’s nice if the thing works when I need it.
I got it cheap as a non runner but it was only one of the switches on the front in a halfway position and dirty contacts on the relay.

I’ve modded the wire feed.quite substantially. I’ve also had problems with the torch wire sheathing constantly pulling off the earth tag inside, as it’s only fastened with a cable tie. Great idea, not!
The little grey cells, as Hercule Poirot would say, kicked in and I came up with an idea that got rid of that problem and gave me something firm to attach to.

 

[skotl]

Good luck! I learned a lot about welders and welding fiddling with my old SIP.

 

[Alan Reynolds]

Good luck! I learned a lot about welders and welding fiddling with my old SIP.

Hi Skotl.
Thank you for all your help.
I modified my welder and turned it on. Nothing went bang, but nothing worked.
I rechecked everything and it all looked good. I had half decided to put everything back as it was originally but I thought I’d have a measure around. I took the gun apart and measured the trigger lead out, back to the bridge but it was open circuit. I concluded that the lead must be broken somewhere.
Sure enough, as I pulled on the wire from the welder end, it pulled out. But it had solder on the end of the broken wire.
I couldn’t pull the wire out from the gun end and I couldn’t feel a lump in the sheathing. I had to pull out the wire feed, the gas line and the lead to the relay. That gave enough room to pull the cable through.
I replaced the cable and re threaded everything back.
Turned it on, and bingo. The wire stops immediately and the multi turn pot gives me wire speed from practically zero to more wire than I would ever need to feed.
So I tried a first weld.
What a revelation. The picture is of the first weld, without setting the current or speed.
The difference between the old weld and the new weld is brilliant. Well it is to me.
Obviously the current draw of the wire on the old system affect the motor speed to a massive degree.
Thanks for all your help. I’m very grateful.
I know the weld doesn’t look professional but it had good penetration and a steady wire feed and made the correct bacon crackle without spluttering. I only use CO2 pub as but I with invest in some co2 argon mix now I know it will actually weld something that will hold together. ( Hope you got this far.)

 

[skotl]

Hi Skotl.
Thank you for all your help.
I modified my welder and turned it on. Nothing went bang, but nothing worked.
I rechecked everything and it all looked good. I had half decided to put everything back as it was originally but I thought I’d have a measure around. I took the gun apart and measured the trigger lead out, back to the bridge but it was open circuit. I concluded that the lead must be broken somewhere.
Sure enough, as I pulled on the wire from the welder end, it pulled out. But it had solder on the end of the broken wire.
I couldn’t pull the wire out from the gun end and I couldn’t feel a lump in the sheathing. I had to pull out the wire feed, the gas line and the lead to the relay. That gave enough room to pull the cable through.
I replaced the cable and re threaded everything back.
Turned it on, and bingo. The wire stops immediately and the multi turn pot gives me wire speed from practically zero to more wire than I would ever need to feed.
So I tried a first weld.
What a revelation. The picture is of the first weld, without setting the current or speed.
The difference between the old weld and the new weld is brilliant. Well it is to me.
Obviously the current draw of the wire on the old system affect the motor speed to a massive degree.
Thanks for all your help. I’m very grateful.
I know the weld doesn’t look professional but it had good penetration and a steady wire feed and made the correct bacon crackle without spluttering. I only use CO2 pub as but I with invest in some co2 argon mix now I know it will actually weld something that will hold together. ( Hope you got this far.)

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Excellent news! Well done - it's a nice feeling when it all comes together