millermatic 250 problems

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have a millermatic 250 that stopped getting gas an not burning as hot.took cover off an found small bunned spot on the aluim cooling  plates that holds the scr rectifier.would this cause the problem an what made this happen. need some help!!
Reply:I dont know about the cooling plates, but there is a solenoid in the back that controls gas. It is very easy to change. Just 2 wires and a nut.
Reply:put new one on it didn't work then i seen bunt spot on the plate
Reply:A failed SCR (one of two) would result in a reduced output and the inoperable gas valve could be either a failed valve solenoid or a PC1 control board problem - which may have been caused by and be related to a non-functioning SCR.  The burn spot could be the result of a poor connection (due to oxidation of the aluminum heatsink plate) which could have caused a SCR failure.  Alot of 'ifs'.How are you at troubleshooting electronics?MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Similar problem with my 250 about 4 years ago.  Our LWS (Airgas) has a repair shop about 50 miles away.  Had to replace a circuit board.  No problems before or since.  Only problem was I was without MIG for a week.TurkeyLincoln Idealarc 250Millermatic 250Miller Synchrowave 250 Miller Synchrowave 350Thermal Arc PlasmaHH140Miller Diversion
Reply:i can do testing with votemeter but not big in electronics can't afford to pay an get fixxed.Would  bad SCR won't make the gas valve not workLast edited by pitbull82jd6; 01-19-2010 at 09:40 PM.
Reply:checked control board for burnt spots didn't find eny
Reply:Start with the simple.  Check all the plugs at control board PC1, transformer T1 and all harness plugs and connections to make sure all are properly pluged in and secure.Do you have a manual for the unit?  If not, get a free download one here http://www.millerwelds.com/service/ownersmanuals.php by entering its SN and highlighting 'Millermatic 250'.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:thanx will be back on tomorrow