Help - 100EN tubo gasless - just starting and nothing

[BobProperty]

I have eventually got the 100EN, that I acquired ages ago, to the front of the garage and want to start using it. So, some scrap angle iron, cleaned up with an angle grinder, gauntlets, borrowed mask, ready to go. Nothing. Touch wire onto metal - nothing.
I have checked that the relay moves when I pull the trigger. Wire feed works. I have checked the thermal cut out as per another thread on here and it seems OK. I have checked that as far as I can tell there are no stupid broken wires or anything like that. What else can I check?
(This is a very second hand gasless Clark 100EN turbo, it allegedly worked some time back but has been in the back of the garage for several months and has only been moved around.)

 

[rtbcomp]

Stating the obvious - have you got a good earth connection? The earth clamp should be tight onto the workpiece which itself should be ground back to shiny metal.

 

[BrokenBiker]

^^^^what he said, return lead is the most important connection. also check inside the torch body to make sure the high current power lead is connected properly, and is tight, no corrosion etc

 

[rtbcomp]

You could try striking an arc on the earth clamp itself - IIRC it's just a crocodile slip and not a very good one at that.

 

[BrokenBiker]

You could try striking an arc on the earth clamp itself - IIRC it's just a crocodile slip and not a very good one at that.

probably be the same as the cheap crap one that was on my mightymig, I swapped it for a 400amp all metal clamp, made a massive difference, as did the euro torch

 

[BobProperty]

Stating the obvious - have you got a good earth connection? The earth clamp should be tight onto the workpiece which itself should be ground back to shiny metal.

The workpiece has been ground back to shiny metal. The earth clamp, as brokenbiker says, isn't the greatest bit of equipment but as far as I can tell it is in contact and hasn't got a fractured cable or anything like that.

^^^^what he said, return lead is the most important connection. also check inside the torch body to make sure the high current power lead is connected properly, and is tight, no corrosion etc

That bit too looks OK, cable crimped on, no corrosion.

 

[BobProperty]

Stating the obvious - have you got a good earth connection? The earth clamp should be tight onto the workpiece which itself should be ground back to shiny metal.

Right, back again. There's only 1ohm between the end of the workpiece and the end of the earth cable, so that shouldn't be an issue. What to check next?

 

[rtbcomp]

Continuity between the tip and output of the rectifier, then see if there's a DC voltage between the tip and earth clamp, this should vary with the power setting.

 

[BobProperty]

Continuity between the tip and output of the rectifier,

I think I've done that. Continuity exists between the wire at the tip and a fat cable bolted to something in the unit.

then see if there's a DC voltage between the tip and earth clamp, this should vary with the power setting.

What range of DC voltage am I expecting? (That's partly because of my multimeter having various bands) Also, won't this be the "wrong way round" as it's gasless, so the earth is positive?

 

[rtbcomp]

Set it to the 100v range, it could be anywhere from 20 to 100.

It doesn't matter if the earth is +ve or -ve, you'll still get the same voltage. If you have a digital voltmeter it will allow for the polarity.

If you have an old analogue meter connect the +ve lead to the earth connection. If you're not sure start at the highest voltage setting and watch which way the needle goes, if it goes in the right direction decrease the range until you get sensible readings.

If you don't get any readings, repeat the exercise on the AC setting.

 

[BobProperty]

Right, I rechecked various connections and checked and got 4.5v across the tip and earth clamp.
And for some reason it is now working. All I can think is that some contact somewhere that I've waggled has now made contact where it didn't previously. So, practise, practise, practise now. Thanks for everyone's help and, rtb, very handsome cat.