Problem with gas on a Syncrowave 250

admin

I just bought an older Miller Syncrowave 250 and I am not getting any gas flow.  It seems I am not even getting power to the solenoid.Just wondering if anybody had any opinions on how difficult this may be to fix, it is something I can probably do myself or if I will have to take it in.  I am pretty good at wiring and electrical, and a little knowledge of electronics.  I don't know  how complicated these welders are as I have not opened it up yet.
Reply:Do you have the owner's manual?  If not, you can go to the Miller site and download it.  Back of the manual has the wiring diagrams and such.  That would be the first step.
Reply:Aren't those things supposed to be really simple.  I think my gas solenoid in my little millermatic is just a two-wire dohicky.  Trigger on means gas flow, trigger off means none.  This might not be the exact setup for that tig machine, but I wouldnt expect it to be a whole lot different.  It should be pretty easy to test if you know the required input power to the switch.  I know this isnt much info, but...well...maybe it will spur someone else to post.Last edited by smithboy; 12-06-2005 at 02:49 PM.Smithboy...if it ain't broke, you ain't tryin'.
Reply:With the manual, it should be fairly simple to find out if the solenoid is getting power.  As Smithboy says, it's either getting power or it isn't.  If it is getting power - replace the solenoid.  If it isn't getting power, check the contacts and then replace the switch.
Reply:Ok, just did some more looking.  I tested the solenoid, it is good.  I am getting power to one side of the solenoid, but obviosly not the other.The schematic is a little hard to read as it looks there there are 3 triggers that can turn on the solenoid.  Pre-flow, which I don't have, Post flow and a 3rd I haven't been able to figure that one out yet.Also, a question on the high frequency start.  I cannot get the arc to jump, I actually have to scratch start.  Is that normal?  I will probalby post this as a seperate question.
Reply:Hi freq is not working properly.  Check to see that electricity is moving across the contacts on the hi freq unit when it's set to continuous.  Looks like the contact points out of an old chevy.  DONT TOUCH IT THOUGH.  It will make you dance if you grab the wrong part.  If no current travels across the gaps, then the gaps might be wrong.  Check gapwidth and correct.  If that doesnt work, the points may be nasty.  Clean them with emory cloth or light sandpaper.  It's the same procedure as for making old car points work a little longer.  There are only like 4 or 5 parts to simple high freq units.  All are pretty generic and easily fixed or replaced with standard stuff from an electronics supply place.  Get the gas going and then sort out hi freq.  You cant tig without gas, you can without hi freq....sorta.I dont know the syncrowave machine, but I think most of the basic stuff is similar across most miller products.Last edited by smithboy; 12-06-2005 at 04:11 PM.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I don't know if this could be coincidence, but in the troubleshooting it says if there is no gas flow, no high frequency and no 120v at the receptical, then reset the breaker.  Well, I might not have high frequency and no gas, but I do have 120v.   Guess I will have to open thing thing up.  But I will test the voltage across the contacts.
Reply:Dont test the voltage.  Just look to see if there is electricity flow between the contacts.  You can see the arc across the contacts.  These things put out thousands of volts at low amps.  It will probably fry your tester and might light you up also.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Ahh, I see.  I will have to give that a try tonight.  Thanks for the info
Reply:do it have a foot switch ? if the foot switch is not on do you hve the switches set to run with out it ?
Reply:I have it set so the foot switch will turn it on.  Still trying to understand the schematic.  They definatly don't make them easy to read.  Not to mention, once the welder is opened up, trying to trace a wire is another mess.I am beginning to think it could be a relay, but I will have to wait until tomorrow to test.
Reply:Good point Chopper.  I entirely forgot about the foot control.  On my welder there is no contactor switch, so I have the switch in the pedal control the hi-freq.  Might the two symptoms come from a bad or non-functioning switch in the foot pedal?  I assume you can run both hi-freq and gas without the foot pedal.  If you set your welder to run without it, this might eliminate the pedal as a problem.  Just another stray thought.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Well, after fiddling with with it a bit, and trying to trace wires I powered it back up to run some voltage tests, and low and behold....IT WORKED!!!!Kind of concerns me that there might be a loose connection in there somewhere.  Gas works just fine, and high frequency now works as well.Thanks guys for your help.  I am definatly better aquinted with my welder.  Now to start to learn how to tig.
Reply:Hey, great!  You are probably right.  Something minor, but it might be tough to find if it only happens on occasion.  Maybe you just needed to jiggle it a bit, like a toilet handle...Smithboy...if it ain't broke, you ain't tryin'.