SUNKKO 709A - Dropped wire

Wayne's World

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OOPS. I'm modding my Spot Welder for better performance and cooling. I've removed the gantry behind the front panel and used the wires to double the current capacity to the pen. In the meantime, I've dropped a wire to the main board - the small red one from the front of the transformer.

Anyone got one of these that they could kindly take a photo showing where this wore connects to?

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There is what looks like a broken wire at the 'HOT OFF'.

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While I'm at it I'm going to install a cooling fan on the back panel. It'd be great to find a ready made 12v or 24v rail as I've got fans of either voltage. Otherwise I'll wack a small PSU board in there and run it off the mains switch. So anyone know if this exists in there?

edit: It could go to the foot pedal socket as there's a broken wire there to. The microswitch wires came adrift as I was dismantling so this will also leave 2 broken points to, but I won't be reinstating that... I wish I had taken some photos DOH!
 
I have one, I will take it apart after lunch :)

I had the idea to upgrade mine after seeing this video:

I wanted to spotweld 0.3 nickelstrip in a 3S8P configuration, but the pliers got really hot and had to stop.
Also noticed that the onboard spotwelder(thing that sticks out) makes spotwelds much easier then the pliers do.
 
Bigfoot48 said:
I have one, I will take it apart after lunch :)

I had the idea to upgrade mine after seeing this video:

I wanted to spotweld 0.3 nickelstrip in a 3S8P configuration, but the pliers got really hot and had to stop.
Also noticed that the onboard spotwelder(thing that sticks out) makes spotwelds much easier then the pliers do.
Thanks Bogfoot. I assume you're referring to the pen (pliers).

I connected it to the HOT OFF point and it blew a fuse after I pressed the pedal a couple of times. It didn't clunk like it should though, so I think it must go to the foot pedal switch (the left most terminal)...

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I to was inspired by that and another video. Here's the fan and a recovered 12v PSU...

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While I was at it. I replaced the mains cable with a higher rated/thicker conductor lead.
And as you can see here, I added the spring loaded terminal cables to the pen connections. I've been thinking I should increase the size of the pen cables. Like you said - they get quite hot after a few dozen hits.

image_ygygzo.jpg



This thing would never pass Australian Standards. The sticker says 15A max, has a 20A fuse, and comes with a 10A plug, and I doubt the lead is rated for 10 amps.
 
I just tested the foot pedal socket. The left most terminal is open circuit regardless of the foot pedal state. It only closes to another terminal when the pedal is not plugged in, so its just a bypass for the built in welding contacts, to ensure both switches are not active at once. The micro switch for the built in contacts is N.O. so removing it will have no effect on anything.

So its either the HOT OFF, and I've messed something up, or another connection on the board that I'm not seeing. Surely taking the other hot wires from the top of the tranny and combining them with the original ones for the pen is not causing some kind of inductance loop.
 
I think I have it right. I just had another scope of the board and found broken solder joints at the yellow cap at the top that I had knocked in my efforts to get the board out. Once re-soldered the unit energized. However, after about 3 foot taps, the fuse blew. I had put a 15A in, so that tells you its really sucking the power. I reckon I need to install a dedicated 15A (or even higher) dedicated circuit. That explains why my office light dims monetarily. So at least in the meantime - it gets its own GPO socket. I'll report back if these changes have made any improvements to the welding or performance.

I noticed that 2AG fuses are harder to come by, and I have heaps of 3AG, so I replaced the holder for 3AG.

So what did I end up changing in this machine...
- Uprated power lead to deliver more power from mains
- Replaced 2AG fuse holder with more common 3AG
- Installed a fan and 12v internal PSU to drive it (routed from switched mains)
- Removed built in spring loaded welding tips, mounting and micro switch as I have never used them
- Cut the mounting down and kept a small part to mount the 3 pin triac (or whatever it is. I didn't look)
- Rerouted cables to built in tips, to external pen connection for double current capacity (to the connection at any rate)
- Made a few errors in broken wires while figuring out how to pull it apart

Once this machine has paid for itself, I might invest in a KWeld or similar.
 
Well it works but I'm not happy with it. I just can't get good welds. Its never been great though.
 
Bigfoot48 said:
I have one, I will take it apart after lunch :)

I had the idea to upgrade mine after seeing this video:

I wanted to spotweld 0.3 nickelstrip in a 3S8P configuration, but the pliers got really hot and had to stop.
Also noticed that the onboard spotwelder(thing that sticks out) makes spotwelds much easier then the pliers do.
Long lunch?

I'd still like to see if I have it correct if you're able? It only works when the power knob is above about 70% so I've messed something up.

I had the opportunity to open up a unit of same model a couple weeks ago but the cuircuit board was completely different and of no help, so keen to see if yours matches.
 
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