I rescued this old Hobart from a scrap pile in Phoenix. There are no tags or name plate on it. I was attracted to it because it is an AC/DC generator welder. Usually these old ones are strictly DC (at least the ones I've seen for the past 30 plus years).
The local/remote switch is missing and the fine adjustment is frozen. I figure it was switched under load and fused itself in position. I believe that is why it ended up on the scrap heap.
I just got the engine running and it purrs. I now am going to concentrate on the welder output side of things. Once running I am going to have it painted and matched to a home made trailer I am currently working on.
In addition I will be attaching an old Miller high frequency unit (pre 251-D) and an old Miller remote switch. I hope it will be adaptable the plug on the panel. A wiring diagram would help me figure the correct pin out.
Questions: Can someone point me to a source for the local/remote switch? Does anyone have a model for this machine and specs/drawings/manual, etc.?
If the fine control rheostat is damaged beyond repair, is there a source for replacement or rewiring it? How about the gauges, any sources for those? It has an amp meter and voltmeter (and another electrical gauge I could not identify due to the frosted glass and an oil gauge).
Attached are pics of the machine and it's soon to be home on the trailer. I have since added a folding table on the side for field fabrication projects. I am debating adding a cherry picker on the rear for heavy objects. It implies fabricating outriggers and more time/money. A luxury I do not have much of these days.
Hobart made eight (8) different models of this welder. Gas drive models : GF - 250 , GR - 303 , G - 400 , G - 412.
Diesel drive models: DB - 300 , DB - 400 , D - 400 , D - 412.
This welder is capable of the following welding process' :Stick,Tig,Stud welding,Carbon Arc Gouging,Flux Core.
As far as parts go. Call older welder repair companies that have been around for a long time.Chances are they might have parts for this older machine laying around or they may be able to direct you to a parts source.Good luck this machine is a great welder if you get it running again.
Thanks for the replies. The model numbers provided put this thing as a GR-303. However when looking at this model online I find that they are all 6 cylinder. Mine is a four banger.
Does this mean that the GR-303 (meaning 300 amp I assume) comes in different engine configurations? Mine looks identical outwardly as the six cylinder models I have found online.
Can I call the tech support line of Miller and ask if they can narrow down the exact model based on GR-303 as the starting point?
Also, the paint on the front panel is actually a faded blue mixed with light surface rust. The rest of the sheet metal is a silver/grey color. One person I spoke with at Bill's repair service which repairs/restores old Miller SA200 machines (http://billswelderrepair.com/) thought it might be a surplus machine.
What do you all think about what model it is or spec number?
Last edited by therrera; 05-31-2009 at 02:14 PM.
Reason: more clarification
I kinda doubt this machine is military surplus.But could be. Hobart Brothers Co. used to paint the machines gold and blue. Check on the main generator for a manufactures plate. But,Usually the plate is located on the outside of the machine under the settings. Also if this equipment was owned by the miltary it should have a spec. on it somewhere that they apply to all their equipment.
I'm not familiar with this model & do not own one. My Hobarts are both pipeline/mainliner style on wheels from the early 50's.
There are some similarity of certain parts as I guess they might have incorporated available parts from current models into the newer models as they rolled off the assembly line.
For example, the empty space your machine marked "local/remote" is shaped perfectly the same as my models "straight/reverse" switch, so most likely that would be a DPDT switch which in my case is used for polarity reversal.
I don't know what the "Local/Remote" would control? perhaps switching power from welding leads to the generator outlets?
You'll really need one of the Hobart experts to join the discussion with hard facts & hopefully provide the actual model# & schematic.
Good luck bringing it back from the dead, getting the engine running well is a big step headed in the right direction.
I know firsthand It's quite a lot of time, money & effort but at the same time very satisfying when you can restore an old machine back to its former glory & get some use out of it...plus, everyone will be wondering what you're smiling about when you fire it up each time !!
take care & have fun!!
That is a G-3010 welder built in the mid 60's. It was powered by a Willys engine and provided 300 amps of AC or DC welding output at 100% duty cycle and had a 10 Kw AC auxillary power output. The multi pin connector on the front was for a tig control attachment. I would contact Hobart and see if they still have a manual for it.
It appears that my machine is the G-3010. I called Miller and ordered a wiring diagram. The tech gave me a spec number to use since I could not provide one due to the missing plate on the front panel.
The missing switch issue is on my immediate agenda as yesterday and today I took the front panel apart to deal with the stuck coarse adjustment control.
It turns out that it stopped welding and was stuck because 1) the small ball bearings (two of them) that provide the stop (click) as one rotates the dial from one heat selection to the next, were stuck (rusted) in place. These have been freed. and 2) because upon disassembly I discovered that one of the two copper straps that provide current to the leads from the coarse wheel had come unsoldered (no doubt from overheating) thus breaking the circuit needed to pass current. I cleaned everything where connections are to bright shiny new and will re-solder the strap tomorrow.
Now for the switch. I was mistaken when I reported that there were three leads going to it. Upon removing the top sheetmetal and looking down into the back of the panel (to deal with the stuck coarse adjustment wheel), I discovered a fourth lead that had been cut near the missing local/remote switch. Since I don't yet have the wiring diagram I don't know what goes where. Maybe someone can fill in the missing pieces.
There are two yellow wires and a red and green one that have been cut. If they all go to the missing switch, then the switch must be a double pole double throw switch. Am I correct? Does anyone know on what pole these go on the switch? Am I correct in assuming they are all from the switch or is the "newly" discovered red one go to something else? IF this is the case, then the two yellow ones go with the green on on a single pole double throw switch. Correct?
here are pictures of the disassembled current control, both coarse and fine. They were full of corrosion which I have since polished up to like new and will assemble it tomorrow. I am still stuck on the correct wiring of the cut leads that I think go to the local/remote switch. Remember the switch was missing from my unit and all I saw were these cut off wires.
The reason the welder was scrapped appears to be due to melted solder of a set of copper leads (one of two) that broke the circuit (see pictures).
The other one shows heat damage to the soldered joint and I will resolder it as well.
Can anyone tell me how to hook up the loose wires near the local/remote switch area? They are two yellow, a green and a red lead.
I recently cleaned up the controls on my hobarts, they are similar and work off the same principles.
It was my first instinct to assemble them dry, because using lube in parts like this usuallly attracts grit & buildup , but I noticed after dry assembly they really needed some sort of lubrication- the wheel seemed too hard to turn, I used a little dab of clear dielectric grease on all the contact points and used white lithium grease on the body where it contacts the backing plate & packed the cavities for the ball bearing stops, The control is very easy to turn now & should be for some time to come.
I ran accross This thread where Steve Crum mentions his G-3010 and how Miller emailed him the wiring diagrams/manual..maybe you can ask Steve to pass them along to you if the folks at Miller are backed up and you're still waiting.
Sounds like you're on the right trail and your new toy/tool will be making sparks in the near future
Good Luck with the project - doug
Well, the selector switch is like brand new inside and I cleaned all the connections going to it behind the panel. The engine is running like a top. I put a welding stinger and ground clamp on it (borrowed from my other welding rig) and tried to get an arc.
Nothing but a few faint sparks when I touch a welding rod to the ground clamp. I will check out the condition of the brushes tomorrow (later today actually) and if they are alright, go on to "flash" the unit following instructions from a manual for another Hobart sent to me by another member of the forum on June 1st. (I only have the email, not the handle).
I have not been able to replace the local/remote switch on the front panel because I don't know how to connect the four wires that have been cut from it. It is missing along with the local/remote switch. There is are two yellow leads, a red and a green one. The wiring diagram I ordered form Miller has yet to arrive.
My question is: Can this machine weld despite the presence of the local/remote switch? Should it still put out welding amperage via the coarse settings? I had thought of connecting different wires in different combination to see if current passes through but am afraid I might damage something.