Millermatic 252 problems

[WILDGSXR]

I have a 252. It doesnt have many hours on it. Yesterday i welded a few things up with no problems. Today, I go out to finish up. It turns on and meters come on and you here the relay kick on when you switch it on. When you squeeze the trigger, it does nothing. No Wire Feed - No Gas - No Arc.
I pull the plug on the gun and ohmed it. Switch is working fine. I jumpered the wires on the plug at the machine and nothing. I checked the power at the receptical and both legs have power. Anyone ever had this problem ? Any help Would be appreciated.

[aametalmaster]

I was going to guess one of the wires on the switch one has come off. I have seen it at least 50 times in the shops. Esp with the M-15 and M-25 guns. But if you checked it looks like Plan B is needed...Bob

[WILDGSXR]

Yea, The gun was the first thing i checked. I didnt have time to pull the cover off of it today. It seems like a relay or contactor isnt kicking on. never been inside of it. i hope its not to complicated in there.

[Meltedmetal]

If you can do it safely check the main switch under power as they can ohm out okay and still not carry much current. And for good measure check all the connections to see that they are tight.

[Aeronca41]

If you can do it safely check the main switch under power as they can ohm out okay and still not carry much current. And for good measure check all the connections to see that they are tight.

Good advice and a key point. Emphasizing the safety aspects again, one really good check is to measure the voltage drop across the switch while welding. Should be very very low, probably millivolts if the switch is good. Put one meter lead on each side of the switch on the same power leg. If it is conducting current efficiently the reading should be virtually zero.

[WILDGSXR]

ok. I will give it a try. thanks !

[WILDGSXR]

After messing with it a little more. The spool gun works fine. it is just the mig gun that wont kick the machine on.
I took the covers off and checked the back side of the plug. it shows to be fine. I checked the voltage on both sides of the power switch and they are both good. i cut the tie wraps and located the 2 wires that go to the plug on the gun and i traced them up to the plug on the board. i shaved the insulation back on them and ohmed them when i squeezed the trigger. They are good up to the board. i even took a jumper wire and jumpered them. No Luck there.
I dont see any burnt places on the board or any swelled capacitors that i can notice.
I really thought that it might have been a bad relay, but it only seems to have the one contactor inside and it seems to be functioning with the spool gun.

Anyone have any more suggestions ? I got laid off a while back and ive been doing odd jobs to pay my bills. i really need this machine and cant afford to carry it in. Any Ideas would be greatly appreciated !

[aametalmaster]

https://www.millerwelds.com/files/ow...30693L_MIL.pdf Look at page 27 and check your Run In. Settings..Bob

[WILDGSXR]

Thanks ! I will try some of this when i get home tommorow. I tried some of it that i watched on a video from You Tube, but it didnt explain it this extensive. it didn't dawn on me at the time, but it has to be recognizing the trigger on the gun, or it would not go into diagnostic mode when I hold the trigger and turn the power on. Again, Thanks very much for the info !