millermatic 251 no weld question

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yesterday my neighbor asked me to help get his millermatic 251 welder going. he says it turns on it clickes when he pull the trigger and the wire feeds out. but is will not strike an arc.no i have yet to look at it before i asked a few questions. when i did maint and had to work on these like 30 years ago if it did this it almost always was the contactor the energized with the trigger. it would either not move when it was told to or it moved and the contacts were dirty. but this machine had a few contact relays so before i spend hours looking at the internal wire diagram it may be possible this one is different. this one has a circuit board years ago the welders i maintained did not have these, so it is possible that board has failed. the cap bank does not show any blown caps on it so if anyone happens to have any ideas where i may start looking that will be a big help. i figure the fist i siwll do using the wire diagram is trigger output and then back test from the gun outputs back to the first point of power. thanks
Reply:If the board or main rectifier have failed it should give a code of HL.P 003 on the digital displays.  That's the only think aside from a poor work connection or bad contact tip that's mentioned in the manual.Check out my bench vise website:  http://mivise.comMiller Syncrowave 250DXMillermatic 350P with XR AlumaProMiller Regency 200 with 22A feeder and Spoolmatic 3Hobart Champion EliteEverlast PowerTig 210EXT
Reply:thank like i said i have not yet messed with it. he said it had no codes but i will have to go over there and turn it on and see what it does. but that code is a help for starters and i will let you know what i find  he told me he cleaned all the connections and when he turns it on the gas works the wire feeds so the trigger is working and it has the displays showing but he didn't say what codes he got if any, and i think he said he ca change the voltage. does anyone happen to know what TP i can probe to test the board?  so if i probe  7 and 8 for input to the diode pack and get power the main transformer is outputting to the diode pack?and then prob 44 and the tip or the positive to the gun and no power the diode pack is bad ? or the main pcb is bad? correct that is how i see it at this point


Last edited by corvairbob; 15 Hours Ago at 11:57 AM.