Post By SND
At work we have a Hobart CW-300-S that was bought in 1987. It has the 130S programmer, meter kit and water cooler. Very nice machine, I didn't know they made them that nice 20 years ago.
Fairly recently the HF start has apparently stopped working. I haven't done much investigation yet as I just started working there today. The machine is used mostly for low amp Tig welding. Often only in the 10 to 30 amp range.
They had a service tech in a few weeks ago, who happens to be a salesman. He said that something on the board has fried and a replacement would be around $1500.
We found the manual for the machine today. It says that Hobart had established an Exchange Service Plan. It says that defective parts could be sent back to hobart. Here's what it says, quoted from the manual : " Under the Control Module Exchange Plan, the owner of the equipment may exchange the entire module in with fault has developed for a replacement. A standard exchange price has been established for each module design which applies, without regard to the amount of repair required to the original turned in, which is applied against the cost of the replacement."
So is that plan still alive ?
I used the machine a bit today. I can get the arc started by just doing a scratch start. Although for the type of work done, HF is a must have. I want to check the Spark Gap before we got any further though incase that is the only problem. I have to take the whole cover off to get to them don't I ? I haven't found where they are supposed to be located from just looking at the manual.
Also, the amperage setting on this machine is quite strange to me. When I look at the dial. It would appear to me that the machine goes as low as .1 amp. but the manual says it only goes down to 5amp. The dial for setting the amperage has 100 divisions on it. One full turn of this dial turns another dial behind it to 10. another full turn turns it to 20, 30, 40, 50, 60,70 and so on for every full turn. Machine is suppused to only go to 400amp. so every turn is defenatly not 100 amp. But what is it ? it would seem to me that every division of the first dial is .1amp. One full turn only seemed to be about 10amp, and 2 turns looked close to 20 if I compare to other tig welders I've used. It just barely burnt thru a .025" steel sheet with the pedal to the floor. Maybe this machine has an extra fine adjustment, did they come with that?
So if it turns out that its more than just setting the arc gap. Is it still possible to get the replacement part for the board at a reasonable price ? We'd defenatly like to get the HF working on it again but if its $1500 for the part, we might as well get a new machine.
This machine was about $6000 new 20 years ago, that would compare to what, 25K in today's money?.
Thanx for any help regarding this machine.
I posted this over at horbart welders also, but thought I'd put it on here too incase one of you guys know.
Miller bought out Hobart some years ago.
But very first, you need to talk to Hobart.
I kinda doubt they still have an exchange program on a 20 year old welder- my guess is you are gonna have to pay the $1500, if thats really the problem.
With the advances in electronics, a welder like that will cost today less than it cost 20 years ago- not $25,000, more like $4000.
New inverter power supplies are amazing, and the biggest Miller tig welder they make (they dropped the aerowave) is well under $6000, even with all the options possible.
You should go look at the new ones, and try them out for your application, because 20 years is a long time for something as electronic heavy as this guy- it might be time for a new one.
Considering the age if we were to start putting 1500 dollar parts in it, it may never stop. Which is why if it is the case we'll look for a new machine. I'm just not buying into what the salesman/service tech said, just yet.
If we get a new machine it will probably be the Dynasty 200. Plasma welding may be in consideration also if it will fit our application.
They defenatly make better welders today with all the same options this one seems to have. For less money than this one was 20 years ago. Although the extremly low amp setting this one appears to have, I've never seen before.
I just meant that 6K then probably had the same value as 25 today.
The amp setting is probably a percentage? Like 100 is 100% or 400 amps, 1 is 1% or 5 amps if thats as low as it goes. That is how my dialarc works although it has 3 heat ranges its dial works from high to low for each setting.
I think once it gets to 100 by going 10 turns. It actualy then jumps 100 amp at the time on the second dial for each consecutive turns, with 1amp increments on the primary dial.
So first 100amps would be going up .1amp at the time and then from 100 to 400 it would go up 1amp at the time. Thats how it looks to me so far. I'll look more into it tomorow. Turns out the machine came with a few different types of faces and programmers.
Turning that dial makes me feel like I'm opening a safe.
That and anything else your capable of checking. With power off Id take a bright flashlight and have a good look around.
I want to check the Spark Gap before we got any further
Well it turns out the HF works. We have to set it to continous to have it work, but of course it says on. If we set it just for Start, it doesn't work at all. Might be a wiring problem, which we will investigate.
Turns out I'm wrong about that dial for the power level too. You may be right that it is as a percentage.
There's good chances we'll have a new inverter anyway.
Help! Just got one for myself, too many dials!
Just upgraded to one of these from a Harbor Freight toy that died on me.
Once I moved the jumpers for 220V it seems to work fine, but I'm at a loss to adjust it.
Would like to see the pertinent pages from a manual, or even a brief explanation.
For my use this unit is like a 427 in a Go-Kart, but the price was right.
I will mostly be welding .062 wall mild tube.
Once I get decently good with this I will want to weld heavier wall and aluminum.
I had one of those machines, but I recently sold it to another PM member. It was a beast, but I never did anything more than test it to see if it worked. Just too much machine for my shop and the work that I do. I remember seeing some 1-amp fuses when I opened it up to look inside. Might be worth checking those out.
Does this machine have alot of analog adjustments? riostates and stuff?
Originally Posted by SND
I own an early 90's miller tig machine, HF went out on me aswell last week. Thinking back to my father fixing his older stereo equip from when I was younger and just spun all the analog adjustments from min to max a few times and what do you know, HF worked again.
This is more of an observation than an answer but I would look around for an active or retired military tech guy with some field work knowledge. In a town where I used to live there was a neighbor who was part of a team that was flown out to Navy ships when the onboard techs were stumped. He fixed audio and video equipment on the side and i seldom saw him replace the entire board. There are many guys around who have the ability to find just the bad component. As expected they have to want to do it also.
My CNC torch was made by these guys - Linatrol Profile Cutting and Shape Cutting Solutions - CNC, Oxy/Fuel, Plasma, Optical Tracing - and recently died with the local diagnose of a bad board. I call the mfg (linatrol) and found out all the techs are long time employees who do not care to just swap boards. They found the bad component and fixed just that for a fraction of the local cost. Great people to talk to.
Maybe, somewhere, there is a guy who can do this for you.
If the HF works in CONTINUOUS mode, just not START mode, that means that the START detection and timing circuit isn't functioning. Typically, it's nothing more than a timer that either has a delay-on-pull-in, or an immediate pull in, followed by a delay, then drop-out... and in either case, the contacts start in the closed-state anytime there's a power request (footswitch?)... and those contacts control the high-frequency generator.
Look at the diagram, you'll see where there's a coupling point between the HF section and the welding leads (there'll be a choke coil just prior to the injection point, and sometimes, it's inductively coupled)... follow the HF path backwards, and you'll see the generation circuit. The generation circuit will be controlled by a timer relay, or if it's newer, a logic line on a circuit board. That timer is what isn't functioning properly.