SA250 TMD feels like it is welding cold

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At work, we just picked up a 1985 SA-250 TMD 2.7.  It feels like it is not making enough amperage.  The outlet has 120v ac, so I assume it is running at the proper rpm.  We checked the brushes and cleaned the slip rings.  It runs great, and it does run a good arc.  Now it might not have a problem, but I just went from running my old SA-200 short hood (1947), and the 200 will weld circles around this 250.  Do I have a problem, or is old just that much better?
Reply:The 1985 SA250 was a descendant of a pure legend IMO... the older DC exciter SA250 models.  All of those I ever had a-hold of were nothing be a great welding machine.  What is the OCV?  To check that put the rheostat on 100 and the machine on high-idle and measure the DC voltage between the welding leads.Let men know if you want and I'll help if I can. lolGood luckLast edited by slowhand; 09-27-2011 at 09:49 PM.
Reply:1780 no load rpm.  105v dc term to term.  varies smoothly down to 50 vdc as you turn down rheostat.  and yes, help would be very much appreciated.  Thanks
Reply:I wanted to clarify what I mean by "feels cold".  I set the 250 next to my short hood.  I have been repairing a large bucket.  I am using 3/16 7018.  I set the short hood at 150amp, 100%.  I set the 250 at 190-120, 100%.  The 250 was still running colder.  I had to set it 240-160, 70% to get it to feel about the same.  I have the leads for both on the same bucket, and was trading back and fourth.  I know I am not comparing apples and oranges, but I expected the 250 to perform better.now I am not a schooled welder by trade, I am a heavy equipment mechanic, but I have done a fair bit of welding.  Everything from rebuilding buckets, to extracting broken bolts by welding nuts to them.
Reply:sounds like your 250 is worn.  possible air arcing in it's past ?  IMO run it just as it is !  My old boss had a Big 50 with that TMD 27 in it.  When he sold it that engine was still running good and he had over 25,000 hours on it.  As long as that thing is still burning rods, i wouldn't worry about it.
Reply:Scroll down on this page for the SA250 manuals. Maybe they'll help?http://www.weldmart.com/technical/manuals.htmOnly 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:Thank you for the manuals.In truth, I do not know anything about the welder's past, aside from the fact that it has been in storage for several years, but I have plans for air arcing in it's future.  I was hoping to spare the old short hood, since that is what I am arcing with now.
Reply:Back in 1985 when that machine came down the assembly line it stopped at setup.  They started the engine and set the RPMs.  With no load the rpm was probably 1800 I would guess (it should say exact rpm in the manual).The OCV was then checked to be at the machine's rating.Then it was hooked to a load bank.  To get the output within the rated range the knobs were all set to max and the brush rack was rolled.  Once the machine was putting out within the rated range the rack was punch-marked for future reference.  I was told this procedure by a Lincoln rep many years ago. lolOf course there many reasons why the output of the welder may be low today and most of those are hardware related issues inside the generator itself.  The engine can also be suspected as to it's ability to hold RPM when under a hard load.  If its pulling down then so will the generators output.And there is also the question as to if this machine has ever been "dialed-in" by someone during the years past.  I can honestly say I have rolled many a rack on SA250s over the years and most of those times I rolled them down (lower output).  This too could be the case here.Good luckLast edited by slowhand; 09-28-2011 at 08:29 PM.
Reply:Thankyou.  The engine sounds like it holds rpm, but I have not checked it.  It is rated at 1800.When you say "roll the rack"  I assume you are turning the brush holder for the large brushes, in relation to the housing?  I will have to open it up again and check for marks.   It sounds like you know your way around these machines pretty well.
Reply:Slowhand, I wanted to give you a big THANK YOU!!  I did not see factory marks (maybe did not know what I was looking for ) so I scratched my own for reference.  I clocked the brushes a few degrees clockwise first to try it.  It woke it up, it seems much better, so I locked it down there.  It also dropped the ocv to 95vdc, which is where the manual says it should be.   It will be a few days before I am into another project to really work it.
Reply:One small step for man, one giant step for mankind.  Congrads man!!!  You just dialed-in your first Sa250.  You should of found a factory punch-mark between the round part of the rack that rolls and the circle that doesn't move it rolls on.  It should probably of been on the left side facing the dials, but some machines just don't have one.  If it ain't there then make your own before you change anything.And remember.... a little does a lot.  Most roll jobs are 1/2 a punch mark (about 1/32" i guess"  then try it.Its best to have an amp meter.  I set the heat at what I want to run and with my amp meter around the welding cable I "stick the rod" and read the meter.  This way it gives me a good constant reading.  I then bump the rack watching my meter.  Usually I'll go 12-15 amps at a time.  Snug the rack then weld with it.A caution.  I'm not much of a fan of sticking a rod with a Lincoln generator for any at all length of time.  That is a dead-short and you know a dead-short is not good on anything.  The innerds of that generator is going to heat up real quick when you stick it so if and when I must stick a Lincoln generator welder I make it as quick and painless as I can on the poor thing. lolGood luck