HELP - Problem with Mig

[andy82]

I have a recent problem with a Migatronic automig 180

I needed to use the migatronic today and the machine has developed a fault.

Machine powers up fine, there is current there but the motor has failed to engage. I can hear the clicking of the relay when i pull the trigger and presume the transformer is fine.

I am thinking that there may be a fault on the board or motor.

I am no good with electrics and dont know where to start, the welder had these problems last week but seemed to free it's self now it has done it again.

It seems to happen if left standing for a while.

Any suggestions on how i can diagnose these problems would be very much appreciated

 

[malcolm]

Ought to be traceable with a volt meter. Between torch and earth should be about about 24V depending on your setting. Won't be less than 18 on min or more than 30 on max. If you get nothing there with the trigger pressed then possibly dirty relay.

If you do get the expected voltage there then unplug the machine and open it up to check the motor wiring to the board isn't dirty or broken.

If that's OK you could plug a 12V feed into the motor from a car battery to see if if works. If that works and the wiring is OK it would point to something on the board.

 

[andy82]

Thanks for the reply Malcolm, you say Between torch and earth (excuse my lack of electrical knowldege) but where exactly do i check please.

If i get to the stage of trying the motor and all is fine, would the board be repairable.

 

[malcolm]

Measure the DC voltage between the contact tip and the earth clamp while you pull the trigger on the torch.

Might be a bad connection somewhere or could be the contacts in the relay itself. Often these can be cleaned up with a bit of sand paper. There are board repirers around if that doesn't work.

 

[andy82]

Thanks Malcolm, I feel realy stupid asking these qustions - but here goes. Looking at the board there are loads of small diodes, abig orange capacitor thing and 3 or 4 white plastic things with layers of something in the middle ....lol i know, i am a big novice on this side of things. These white things dont look like relays and cant seem to find any others apart from the big black relay unit that clicks when i press the trigger

Thanks for the help malcolm but i am totaly clueless

 

[andy82]

Update: Just checked the voltage and i am getting sufficient readings.

 

[malcolm]

Might not be the relay in the circuit board if you have voltage to the torch. Do you get voltage across the two wires to the motor too?

 

[andy82]

Hi Malcolm, There is no reading from the wires at the motor when the trigger is pressed

 

[malcolm]

I'd trace those wires back to the circuit board. With the welder switched off check the continuity of the wires from the terminals on the circuit board to the motor. Most likely a break or a bad connection somewhere.

 

[andy82]

I have checked continuity on all wiring from the power relay to the plug on the board, from the plug to the motor. Looking at the power relay I disconnected the top part to try and clean the contacts but only revealed a heat sink thing that slots inside the coil windings of the relay. I can’t seem to get to the internals of the unit. I have now disconnected the board to try and diagnose any faults with the capacitors and resistors but will need to send off for testing.

Have ran out of things to do but sit back and wait for the board to be tested.

Ps. I don’t know if this may be relevant but one of the sand block resistors fell off - presume that may of been loose or I knocked it while taking the board out. So will need that re soldered.

 

[Stuggi]

If it's a newish automig then Migatronic vendors should be able to supply you with a replacement board.