Cosmo Mig Not Arcing??

[shy7g]

Hi all I have a Cosmo 170 gas/gasless mig
I'm new to the forum and have a problem with my mig welder.
My mig welder is a Cosmo 170 gas/gasless mig which has been a fantastic piece of kit for many years until now. I have checked all connections, switching positions etc and all seems OK, the wire is feeding fine also, but when trying to strike an arc all I get is a sparkler effect off the wire to work piece, earth strap (both ends) and even the earthed areas inside the mig unit itself, but to no avail, although once in a blue moon it will arc up and work for a very small period of time until it reverts back to "sparkler mode".
I have included a photo so you can see the configuration of the unit.
All help greatly appreciated
many thanks
Rich


closer photos of the different unit are available if needed, many thanks

 

[shenion]

Does sound like loose connection. Most common on the SIPs is the power connection of the torch at the wire feeder.

Other than that, recheck connections. They may look ok, but could be corroded.

 

[shy7g]

Does sound like loose connection. Most common on the SIPs is the power connection of the torch at the wire feeder.

Other than that, recheck connections. They may look OK, but could be corroded.

For a simpleton like myself could you explain a bit more what to look for with regards to "power connection of the torch at the wire feeder"?
When gun trigger is pulled the feed wire motor is running OK, would this still be the problem even although the feed motor is OK? I previously had a problem with the micro switch in the handle, but having taken the handle apart and blowing out the muck the switch worked fine there after. I've checked/cleaned all the other connections before hand also.
Please advise
many thanks

 

[shenion]

Look where the torch lead enters the machine. The torch power is held on with just a spring clip, if the torch is pulled, it will come loose.

 

[shy7g]

Look where the torch lead enters the machine. The torch power is held on with just a spring clip, if the torch is pulled, it will come loose.

Hi had a good look around only found what's shown in first Photo
ALL CONNECTIONS ARE TIGHT

I did find the polarity connections slightly loose so I put a star washer on each which tightened both up. (see photo below).


Power the unit back up but still the same????
Any more suggestions appreciated.
(could it be the mig torch handle itself???)
Please advise
many thanks

 

[the snooper]

in the picture remove the black tie wrap and check the connection from the brass fitting to the torch

 

[shy7g]

in the picture remove the black tie wrap and check the connection from the brass fitting to the torch

YES checked the connection - all's tight and correct.
WHERE NEXT TO LOOK?

 

[the snooper]

if you have a multimeter check the voltage atthe torch, also any crimped cables they can be physically strong but dont pass current

 

[mike 109444]

shy7g try taking apart the 5 connection shown with "X", cleanup with a small file all the bits of the connections ie nuts, washers, and the cable that they clamp. Note some may have insulating washers make sure you reassemble in same order they came off. As there does not seam to be any contactor I guess the tourch is always live?. If the cleanup of connections does not cure it could be a duff power selector switch. There is a way to test by by passing but try the cleanup first. Looks dusty in that machine : )

 

[shy7g]

Finally found the problems
first was the earth connection in the handle, there was an airline fracture in the crimped connection which holds the cables in place. The crack was on the back side to that of the handle taken off, so it looked OK when opening up the handle, but lifted when attempting to weld.
Second the earth cable again had 95% broken through approx. 6" inside the sheath away from the welder end (so it wasn't visible).
thus why the problems were intermittent
thanks again to you all
so its working again, for now

 

[shenion]

Good to hear

Thanks for posting back what the problem was.