mig welder repair procedures

[the snooper]

start by finding the 2 mains wires that go into the transformer probably one to the relay and the negative to the mains switch or somewhere similar take a photo and write down where they connect to (make a good job of that as it will only cause you more problems if you forget where they came from) then disconnect them both and connect them to your multi meter set your meter to resistance say 200 ohms and you should get a reading showing there is a circuit

 

[dai]

biggest problem is the switch is all connected to thr transformer

im thinking it could be the switch

 

[the snooper]

yes the thinner wires.
if it were the switch nothing would work !

 

[the snooper]

do i spot a bodge on the power selection switch

 

[dai]

no,nothing ive done anyway

 

[dai]

the 2 blue wires running to the transformer are i prusume the thermal cut out?

 

[the snooper]

someone has taped it up for some reason have a look it may hold the key to the failure look for heat damage to any connectons to indicate a bad connection arcing

 

[dai]

someone has taped it up for some reason have a look it may hold the key to the failure look for heat damage to any connectons to indicate a bad connection arcing

just looked at it its the camera angle its a plastic cover

 

[the snooper]

would have been nice oh well

 

[eddie49]

The DC voltage briefly jumping to 40 when the torch trigger is released suggests power coming from an inductive kick in the primary, as the contactor opens and the magnetic field in the transformer collapses. That implies the secondary winding, rectifier and capacitors are OK, and, as The Snooper suggests, the problem is that the primary cannot deliver sustained power. There may be a weak connection anywhere in the transformer primary circuit, somewhere from the contactor to the transformer, or even inside the primary winding itself.

 

[dai]

i got volts thru the contector into the power switch and then nothing
so im 98% sure its the switch anyone know for a supplier??

 

[dai]

the offending article
where can i get 1 from
its has off and 6 power settings on it

 

[dai]

right switch is ok
i can get volts(anything between about 15-30depending on switch setting) into the rectifier (square plates)
how do i test that properly

 

[dai]

this is hardly helping
helps when you look at it in the daylight
the gaps were hairline untill i prodded the diodes with a screwdriver

 

[R Kraft]

Looks like time for a new rectifier module.
Robert

 

[dai]

nothing to loose so out with the soldering iron

 

[dai]

whoos the daddy,whoos the daddy,whoos the daddy,
theres me with a great big grin

 

[dai]

but.............
thats all i could do as i heard a nice big pop and it stopped working again

 

[dai]

on this thread here
that welder seems to be able to burn holes in 3mm steel
for a 200amp set is that normal as mine has never had that sort of power
ocv on mine was about(when working)
setting
1-15v
2-20v
3-25v
4-30v
5-35v
6-40v all approximatly

 

[R Kraft]

Each of the diodes shares some of the amperage.
Yours may have had some problems for a while, a 200amp welder should weld 5mm.
So burning holes in 3mm with one should be pretty normal.
Your OC voltages seem to be reasonable.
Robert