View Full Version : Help identifying old gas drive
05-31-2009, 05:26 AM
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.
Thanks for any help,
05-31-2009, 11:11 AM
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.
05-31-2009, 01:10 PM
Looks like it might be a military surplus machine...is that old green faded paint on it?
05-31-2009, 02:11 PM
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?
05-31-2009, 02:23 PM
Blue/Gray...could indicate either Air Force surplus or even Navy surplus(found location might indicate Air Force). It just hit me with the feeling it was a surplus machine at first look.
It should have some ID plates on it somewhere if it is a surplus unit. Might research online for companies that handle surplus equipment like that for parts or manuals.
I can't swear it's a surplus machine,just that it looks like many I've seen before.
Are the ignition wires waterproof/braided SS coated wires with screw on connections?
Someone will ID it in the next few days....
05-31-2009, 02:58 PM
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.
05-31-2009, 03:43 PM
I have scoured the machine for any kind of identifier. There are none to be found. I looked on the generator unit, the front panel, on the frame, etc.
I will double check today and report back. So far, it looks identical to the GR303 except for mine is a four cylinder, 300 amp.
Thanks for your help,
05-31-2009, 07:14 PM
You may contact with oldtrukluvr member on this board. He have an welder like yours. Sure can help you. Good luck
06-01-2009, 07:13 AM
I'm not familiar with this model & do not own one.
My Hobarts (http://www.cnyara.com/welders/index.html) 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 !!:D
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.
06-01-2009, 02:22 PM
Local remote refers to amp control. Could be TIG foot amp control or rheostat with knob in box to fine tune amps for SMAW.
06-03-2009, 06:07 PM
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?
Any help is greatly appreciated,
06-03-2009, 10:48 PM
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.
06-04-2009, 06:51 AM
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 (https://www.hobartwelders.com/weldtalk/showthread.php?p=296587#post296587) where Steve Crum (http://www.hobartwelders.com/weldtalk/member.php?u=11559) 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 http://www.hobartwelders.com/weldtalk/images/icons/icon14.gif
Good Luck with the project - doug
06-06-2009, 03:18 AM
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.
Any help is appreciated.
06-06-2009, 08:03 AM
Trace the wires and see where they go. One pair of them will need to be connected for it to work. As it is right now it wont work because the machine doesnt know if the amperage control is connected or not. Do you have a wiring diagram for it? If I had it I could tell you what wires done what. One of the wires should go to a plug for the remote control. Just guessing without seeing it.
06-07-2009, 01:04 AM
I determined which wires are local/remote (partially). the two yellow wires each go to the remote plug and the fine adjustment rheostat respectively. Thus I can rule out one wire right off the bat (the one going to the remote plug) which leaves my choices for the fine control to just one of two wires to connect to the other yellow wire, the red or the green (actually green and white).
I tried these but the welder did not produce any welding current. The next step in the plan was to "flash" the exciter as I have read about in other posts. Upon removing the generator cover I discovered that 4 out of the 8 brushes were damaged and missing the pigtail connecting them to the wiring.
Not to mention that I found a rat's nest and tons of rat dropping, nest material, etc. I cleaned all that out and just got through ordering 9 new brushes from Arrowhead Electric Company (http://www.carbonbrush.com/hobartbrush.htm). They have a Hobart page and you provide the dimensions and specs from your original brush and match it to their online grid of brushes. The model I ordered is the W63 which matched mine exactly. We'll see when I get them if I was right, but their measurements matched mine, so I can't see a problem. I should get them within 2 to 5 days.
I then proceeded to bang out some dents on the sheet metal, remove all the gauges and electrical plugs (both 110v and 220v) from the front panel, cut off remnants of the frame mounting iron going to it's original trailer and grinding the old welds flush (it is going on a home made trailer) in preparation of a new paint job.
Where can I locate new gauges for this thing? Are the original ones standard size? This model has two AC ammeters, an AC and DC voltmeter, oil pressure (that one is a NAPA store item for sure), and I even found a disconnected AIR PRESSURE gauge????? What was this for and where did it get its pressure from? Is it an air pressure or vacuum gauge connected to the Willy's 4 banger? I have never seen a setup like this before.
Anyone got any answers, thoughts on this stuff?
Attached are the final pics of the trailer prior to getting its paint job too. It has brackets for 4 bottles. I will set it up with Oxyacetylene bottles, an argon bottle and a co2 bottle. It also has a fold down work bench for on site fabrication with a little comfort. The tailgate doubles as a mini workbench for the little stuff. I will be adding a vice to the plate seen in the picture. I bought the trailer used and it came with an gas driven air compressor which will go mounted in front of the Hobart crosswise, the Welder will mount lengthwise in the center of the trailer. I added the rack (adapted from a friend's pickup), the tailgate and fold down table. It will have a hose reel attached on the front.
I am taking advantage of a slow down in work to get this done. I am seriously considering selling my welding rig and going with this trailer. My rig is an old 60's era NATO Mercedes Unimog TLF-4 firetruck, converted into a field welding shop. Fun to drive, can go where others only dream of, gets a lot of looks, but expensive on gas and not comfortable AT ALL! At my age, I think I need at least a LITTLE creature comfort (air conditioning, stereo, radio, etc.). Don't you? Pictures attached too.
Thanks for any help,
06-07-2009, 07:37 AM
I like the Mercedes!
06-24-2009, 11:44 PM
I am just getting off of being knocked out of commission due to a bum knee. The welder is getting prepped for painting tomorrow as is the trailer. I installed the new brushes and tested with the same result.
Another member on the list brought to my attention that capacitors that hold a charge and are installed on the armature or ring plates may be bad or missing. I will check on this tomorrow. I am still missing a manual that covers my machine as the lack of a name plate on it prevents me from getting an accurate wiring diagram. I still don't know how the remote/local switch should be wired. The manual I was able to obtain using a generic spec number shows six wires going to the remote/local switch, where my welder only has four wires going to it.
I did notice that the on the stator rings, two of the eight brushes don't have any leads coming from or going to them. The brush lead for these two just screw into the connector on the frame. Could these be the two wires that would go to the local/remote switch???
I also ordered a pair of AC ammeters and should be getting them by next week. These will enable me to connect all the wires before attempting to flash the welder. Advice I got from others suggest that if any of the wires going to the gauges are removed or if they are connected to a defective gauge, the welder cannot produce current.
A pair of welding repair techs told me that they are just informational and should not affect the welder producing current. Just to play it safe I am replacing them and connecting all the leads back. One of the gauges is visibly shorted out, so this should eliminate this problem.
I tried writing Steve Crumb to see if I could get a copy of his manual or advice on his G-3010, but have not received a reply. I hope he is all right.
I advertised on our local craigslist for a welder repairman or welder with experience with these machines to see if I can get a hand. A few have responded but we have yet to hook up. I will be able to do more once it is painted and mounted on the trailer and everything is bolted back into place as right now it is still in somewhat of a disorderly state.
Well that's it for now, if anyone has any ideas or answers to these questions, I would appreciate the help.
07-11-2009, 01:27 PM
Usually the remote switch takes the fine adjust pot out of the circuit, so without it you won't get weld output. I don't have a print for that welder, but other old Hobarts are done that way.
07-12-2009, 12:26 AM
Thanks for the reply,
I have tried hard wiring the cut wires going to the local /remote switch in different combinations with no luck. However, I am working with only four wires and I think I need to be using six wires. One set goes to the remote plug and the other goes to the rheostat. I am missing the ones that take the current to them if I am not mistaken.
I discovered some time back while replacing damaged brushes that two of the brushes on the stator rings are missing wires going to or coming from them. Could these be the missing set that go to the local/remote switch?
The paint work has been delayed due to a back log at my friend's body shop. The welder and compressor have been painted but not the trailer they are being mounted on. That should be done by this coming week. Then I will assemble everything and be able to bring the machine home to continue working on it in the comfort of my back yard. I got the gauges but have not been able to install them yet.
09-15-2009, 06:13 PM
I did a search and came up with this thread. It's like reading a mystery novel, and the last chapter is missing! Any updates? I'm tracking down an old hobart myself and am interested.
Please let there be updates!
09-16-2009, 10:33 AM
The thread stopped because I was at a standstill due to a lack of a wiring diagram. It was tentatively identified as a G3010. However another user identified it as a G310 and made available a wiring diagram. In the meantime without it, I could not figure out what wire goes where.
Also I located the correct type of switch I needed which is a double pole double throw, on-off-on switch like the type used to reverse the direction of a motor.
I will be getting back to this project in the following weeks as I was diverted getting a miller mig machine that I need for my work in running condition.
While I continued to search for the information on this hobart I continued the work on the trailer and air compressor that it will be paired with. I had to build out the trailer for field fabrication and get the generator running. Ironically I was held up due to a cracked plastic gas tank which believe it or not costs $140 after taxes!
I was able to get a plastic welder to patch it and it is up and running. I should get the switch by the end of the week and I will be able to post progress after that point.
Pictures can be seen at:
Thanks to the wiring diagram I was able to figure out the type of switch and where the extra pair of wires needed for the remote switch are coming from. The come directly from the welding slip rings via a set of rectifiers. I just have not gotten into that until I get the new switch.
I could have simply hard wired the remote / local wires now that I have the wiring diagram but a second part of this project is wiring in a remote amperage control. I got a hold of a Miller remote control unit and have started another thread asking if anyone has the pin out for the remote unit.
Being that it is just a rheostat, the wiring couldn't be that complicated.
Well, thats the most up to date. I will post more as soon as I get the switch and make some time. It will be within a week or two at the most.
Thanks everyone for your help and input. The journey is almost over (I hope!).
05-17-2012, 04:10 PM
So what happened?
05-17-2012, 09:54 PM
I went to Tony's to check out his welder. Nice Unit for sure. 350A/C 300D/C it's alot like an older Miller Trailblazer 2J with the Jeep Kaiser Engine..Almost Exactly. I own Two Hobart GF-250's one older and one newer and the older ones had the scr board which took the 115vac power from the field windings and run them to the output stator windings through the output brushes to the leads. Of course these field brushes needed to be flashed before any arc would occur. In the Case of the Tony's Hobart I could'nt find any boards in his unit and could only conclude that perhaps the battery or alternator provides some form of flashing to the primary windings. Although there are a few capacitors behind the front panel which I don't know what they are there for. The schematic is a requirement to understand the operation of the unit..
05-18-2012, 12:36 AM
The welder and trailer are exactly where they were a couple of years ago when I took the last pictures of them after getting the setup painted. I got a hold of the wiring diagram for it and got side tracked with work and other projects that came to the forefront, pushing this one back.
I did a job for a client who has contact with a guy who serviced these machines and will put me in contact with him. I expect before summer is out I will pull the trailer out of its parked spot and into my driveway to work on it again. Part of the problem is that I need my driveway for work as I have a welding service and do jobs at home. I figure I will be working on the machine for about a week getting all the things it needs done.
I have an old miller high frequency unit that I bought to pair with this welder to use for AC tig welding. I hope to get to it real soon.
I'll post any new developments.
06-17-2012, 12:07 PM
Don't feel bad. I have one sitting too. I bought a new engine for it but haven't put it in yet.
I picked up a Hobart GF-250 with a 6 cyl ford that is a work in progress too.
06-17-2012, 11:33 PM
I finally got in touch with the welder repair guy. He's an older retired fellow that used to service these older gas drives. He came and towed it to his house where he works out of. The engine runs great and the governor does its job too. I put all the AC plugs and gauges back in their place as the last I touched this machine it had been prepped for painting and all the gauges and stuff on the front panel were taken out so as to not get sprayed.
I put the battery back, charged it up and fired her up after playing with her for a while with some carb cleaner as starting fluid. I put fresh gas in her and when she fired up I could smell the old gas burning out. Very distinctive.
I also tested the armature with the help of a friend to make sure it wasn't shorted. It isn't. Hopefully this means that it is something minor like burned out diodes or resisters somewhere in the circuit.
I expect to have it back by week's end. Hopefully it won't cost me an arm and a leg but I can handle several hundred dollars without eating into living expenses. If he can get it going I may be looking to sell it and finally getting a decent pickup truck. My old work truck was an old 1971 Toyota Landcruiser that was stolen from in front of my house. It had a full size rack that served to haul the iron I used for work.
I'll let you all know how it goes.
06-19-2012, 03:34 PM
With the help of an older repairman of these old Hobarts the machine is finally able to produce AC at the plugs. He reported to me this morning that it excites and produces AC current for about 30 seconds and then cuts out. He is not sure why its doing this and I thought I would post it on the forum here to see if anyone else may have a clue where to focus the troubleshooting.
It has new brushes and all the wiring is in place with the exception of a remote switch which is mission