Trouble with Lincoln Weldanpower No Output

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Hello, I am trying to toubleshoot why I have no welder or power output on my 225 G7. After downloading the manual and going through a series of checks there and reading a couple of posts here, I have some questions if someone out there could help me  with. I have checked for faulty rotor and get ohm reading of 4.4. I checked rheostat resistance and it checks out at 9.9 I checked for faulty stator field winding and have continuity. I was told that I need to have AC first before DC, but this doesn't make much sense to me. According to a previous post, I should check the Rectifier.....There are 2 rectifiers, D2 and D3 according to the wiring diagram. How do I check this?...I should check  the engine alternator for voltage to the capacitor? What is the most likely problem here? Board? I have been all over the connections and all looks good. I have cleaned the slip rings and checked the brushes real good......Any suggestions or advice on how to check the rectifiers or other likely problem areas would really be appreciated. Thank you, Mule
Reply:Welcome to the forum mule.Got a unit code # so I can be looking at the same diagram?Ohm readings are in line.Did you check for stator lead shorts (continuity) to ground?Did it just stop welding and making power all at once or has it been sitting for a while?Have to have DC to make AC to make DC to make more AC.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:Thank you for replying......Code is 9444.I have been using the welder. Went to use it 2 days ago.....no output, sprayed the slip rings, cleaned the terminals to the brushes, next thing it welds all day. Next day I go to use it, nothing...it has just been sporadic. I really cleaned the slip rings, pulled the brushes, put some no lox on the terminals after cleaning them, and went over all the connections with nothing wrong found. As far as the stator, I pulled the leads as suggested off of the D2 rectifier and had continuity between the leads #4 and #5b. I really didn't even know where to begin troubleshooting this machine until I downloaded the manual and started going through the steps in the troubleshooting section of the manual. Thank you again,Mule
Reply:Should only show continuity one way between #4 and #5b at D2.Did you check/clean the rheostat wiper and winding?Check it for a dead spot (wiper loosing contact with winding)?I'm still thinking.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:I didnt check both ways for continuity at D2, didn't know I should of. The rheostat wiper and contacts are clean. My curiosity is around the engine alternator/capacitor/rectifiers at this point. I think I'd really like to know how to troubleshoot this area. The engine runs on high idle, as it thinks it has a load.......don't know if that is any help.Mule
Reply:Forgot to ask - Briggs & Stratton or Onan engine?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:It is a Briggs
Reply:mule, sorry for the delay in getting back to you.I don't have a schematic of PCB1 to confirm a couple things to check there but here's what I come up with based on your checks and figures to date and what you describe is happening starting with a little explanation.Initial DC rotor field excitation voltage comes from the battery thru the START/RUN/STOP switch on circuit 212 and then from PCB1 on circuit 219.  Once the unit is up and running, field control voltage then comes from the stator which is rectifed from AC to DC thru full wave bridge rectifier D2 and so on.So, considering your problem is intermittent and all your other checks to date seem to be in line, I would focus in on circuit 212 from the START/RUN/STOP switch and 219 from PCB1 on thru to the + brush.  Look closely at the plug and terminals on PCB1 and look it over for any broken solder joints at the board receptical and components.Your machine relies heavily on theboard for proper operation as it controls rotor field exciter voltage, battery charge rate and auto idle based on numerous input signals.  As a reference, circuit 212 is at pin #1 and 219 is at pin #2 of PCB1 board connector.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:Hello Duane, I thank you for all of your help so far with my welder. I started this morning and been working on it all day. I replaced the D2 Rectifier and I resolved some of my issues. I now have AC output and weld. I seem to have additional problems in that the machine won't idle down now. I have made numerous checks and here is what I got. I have 12.8 vdc to the solenoid, I put an additional ground to the base, but the magnet doesn't seem to work at all. I am planning on replacing the 12vdc relay too, as the contacts look suspect and I dont see any movement on the contacts. Is the PC board still part of the problem, I am not sure, but it does seem that the idler solenoid isn't working. I may have access to a solenoid and relay from another broken machine.....but I really don't have any reason to know whether the board has a problem at this point. What would you additionally suggest with these latest findings? Thank you, Mule
Reply:OK.  Apparently D2 had failed or there was a very poor connection at it.  A diode (such as in the rectifier) doesn't typically experience intermittent failures.The idler solenoid gets 12VDC + directly from the AUTO IDLE switch and PCB1 controls the ground to idle the engine or allow it run at weld/power speed.  The solenoid base does not need to be grounded at all.  You can check the solenoid by simply grounding circuit #215.  If it's OK the solenoid will activate with 12VDC + at circuit #213 (AUTO IDLE switch in AUTO IDLE position) and 12VDC - to circuit #215.Are you waiting (approximately 15 seconds) for the AUTO IDLE to engage?Relay CR2 is activated by PCB1 to by-pass FINE CURRENT CONTROL R1 to apply regulated rotor field voltage while generating AC auxiliary power.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!