Clark 90en problem

[fljp]

Hi guys,
just jumped on the forum as I have never welded before but currently rebuilding an old golf and being able to weld (basic not flashy bodywork) will be useful
I picked up a Clark 90en the other day, 2nd hand the guy I got it from said it's all good just not man enough for him
problem is when I turn it on the on/off switch is constantly illuminated amber. I'm welding gas less and have the correct wire in there. had it apart and can't see anything obvious. any ideas would be helpful
says in the manual this means it's being cut out as it's got to hot. but I haven't welded at all?!?!?! as if a sensor is faulty and jumping in early?
thanks in advance

 

[rtbcomp]

Welcome to the forum.

IIRC the temperature sensor is on the rectifier on those models and it goes open circuit when the rectifier overheats, so, with the unit unplugged from the mains have a look inside for a pair of thin wires going to the sensor, one of them may have become disconnected.

If they are both in place disconnect them and check the sensor out with an ohmmeter, it should show zero ohms. If it shows open circuit at room temperature it is faulty.

 

[fljp]

Welcome to the forum.

IIRC the temperature sensor is on the rectifier on those models and it goes open circuit when the rectifier overheats, so, with the unit unplugged from the mains have a look inside for a pair of thin wires going to the sensor, one of them may have become disconnected.

If they are both in place disconnect them and check the sensor out with an ohmmeter, it should show zero ohms. If it shows open circuit at room temperature it is faulty.

 

[fljp]

Thanks for the welcome
by the sounds of it, it must be that sensor. This may be stupid, but.... what doe s the sensor look like? completely new to welders remember so bare with me!

 

[rtbcomp]

Most likely a silver button with a couple of spade connectors on it.

 

[fljp]

ok cool, i'll have a look tomorrow. will this part be available at a Clarke outlet? or will I have to order it direct from them?

 

[fljp]

Ok so this is what I'm looking at, I think it's the black circle with two brown wires going to it top middle of the pic (on the silver plate). is that the right piece?

 

[rtbcomp]

That's it. You'll probably have to go to Clarke, but the likes of RS/Farnells/CPC or someone on Ebay may stock them. You'll need to know the operating temperature though.

As a quick check you could connect the two wires together, but don't weld (a short test weld will be OK) with it like that because you may overrun the duty cycle and fry the rectifier.

 

[fljp]

Just tied to run without the sensor, connected the 2 brown cable together with the same gauge wire to bypass it but still no go. The amber light is still on. any ideas on what else it could be?

 

[rtbcomp]

As a matter of interest try it with the rwo wires disconnected.

 

[fljp]

Tried that but still the same response. just the amber light

 

[shenion]

Some of the older models the light is always on.

Could be a wire loose. You can see if you have voltage on the torch trigger wires.

 

[rtbcomp]

You can get the manual here

http://www.clarkeservice.co.uk/manuals/mig_welders/mig90en_151en.pdf

The circuit is for a 100EN, but I'm guessing it's the same.

Have a look at the mains switch, how many wires does it have?

4) then the lamp will be on with the mains
5) then the lamp will most likely be on under fault conditions.

 

[fljp]

Thanks for the help on this, git it going in the end I just unplugged everything and roughed up the connections with sand paper a bit it was stored outside for a while by the precious owner so I think it just needed a good service