Problem with 1977 SA 200 Blackface

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I know this issue has been discussed many times on this website and I believe that I have tried most if not all the posted solutions to no avail.  I own five SA 200's in various states of disrepair and one that I have completely restored. You can see it at [URL="http://www.youtube.com/watch?v=ehzJiNBzRS4[/URL]  The only reason I mention this is so you will Know that I am not a complete idiot.  The following is my problem and what I have tried so far.  I am working on a 1977 Blackface with and automatic Idler Code7789 Serial #A814416.  The selector switch broke (the old phenolic thermosetting plastic becomes weak and breaks).  When the selector switch broke the weight of the connected cables caused it to fall on the Reed switch and broke it also.Since I am a hobbyist and had several other welders that I could use I did not immediately repair this machine.  When I did get around to replacing the Reed switch and associated wiring (about a year later) that was ripped loose the welder would not produce an arc.  It would produce only a sparkle and would not weld.This is what I have tried so far:1.  I can read a wiring diagram and have one so I know the wiring is correct.  I also have most of Lincoln's literature including their trouble shooting and service repair manuals.2.  The Idler board works fine and the idler solenoid worked properly after I cleaned the trash out of it.3.  Since the auxiliary outlet tested 125.5 ohms  on my multimeter and ran a grinder, I performed the DC Exciter Test as suggested by Lincoln.  The DC voltage at the brush holders was 127 volts. Lincoln say's that if the DC Voltage is normal at the brush holders then the DC Exciter armature and shunt coils are OK.  However, I checked the resistance on the exciter shunt coils and could only get 108 ohms so I replaced them with a set I had that read 167 ohms anyway but as I expected it made no difference. 4.  The engine starts and runs at the correct speed (1550 rpm) but there is low to no welder output (4.1 ohms).  Therefore, I checked the fine current rheostat and it measured 64-10 ohms and turned smoothly. Next, I performed the Main Generator Shunt Field Test as suggest by Lincoln.  The resistance value achieved was greater than 500,000 ohms as Lincoln stated it should be.  Next, I checked the continuity of the interpole coils.  They showed continuity from the positive brush holders to the output terminal and were NOT grounded to the generator frame.  Next, I checked the continuity of the series coils.  They showed continuity from the negative brush holders, through the current selector switch, to the negative output terminal and were NOT grounded to the generator frame.  5.  I removed all the main generator brushes to make sure they were not frozen and reseated them.  I also used a commutator stone on both the exciter and main generator armatures.6.  I flashed the fields using Lincoln's published procedure at least three times but that did not make a difference either. I am sure anyone reading this realizes I am no expert and could use any other constructive input or ideas that might cure my problem.
Reply:After 84 views and no replies I am convinced it must be the main generator shunt coils.  Therefore, I am going to remove the main generator stator and take a closer look at the shunt coils.  I do not understand how it could be anything else.
Reply:I don't know the answer but if memory serves 1977/7789 was the worst year for bad shunt coils. You should call Bill's Welder Repair. Kaye knows these like the back of her hand.
Reply:The problem you're having with your machine making sparkles instead of welding is a classic shunt coil in the main generator symptom. I've looked for two days now (off & on) for the thread where Kaye states the 7789 code # is the worst one for shunt coil failure but have been unable to find it. It's either here or at the AWS Forum, but I'm reasonably sure that is the correct code # as Welder Dave states.Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.                                         -Cree Indian ProverbSA 200 LincolnVictor Torches
Reply:Originally Posted by gizzardgutzI've looked for two days now (off & on) for the thread where Kaye states the 7789 code # is the worst one for shunt coil failure but have been unable to find it. It's either here or at the AWS Forum, but I'm reasonably sure that is the correct code # as Welder Dave states.
Reply:Thanks for the info on code 7789, I have already ordered the shunt coils and I will avoid this code in the future.
Reply:You can put copper shunt coils in.
Reply:I have ordered the copper shunt coils and I suppose this should not be a problem in the future.  I have removed the main generator housing (stator) and see that the shunt coils are held in place by a "dove tail" slot.  Does anyone know of a pressing tool that fits the dove tail or do I need to build my own?