New Old Dead Plasma

[whtbaron]

My son bought this plasma cutter with the usual assurances that it was only driven to church on Sundays by a little old lady. We ran it for maybe an hr. max and it was working great... until it wasn't. The on/off switch feels goofy so I'm pretty sure that fried, the real question is whether a new switch will fix it or it something else pulled too much power through the switch. Neither one of us has any experience with plasma's so we were pretty much guessing at what we were doing. It was sold by Acklands so I assume it was re-badged. He was told it was really a Miller and judging by the sticker on it, it was likely sold through a Miller dealer at one point. I also see a Thermal Dynamics sticker on it... any idea what we have here? Will have to find something more local than the stickers indicate for repairs.

[Oldiron2]

Based on the two stickers, [and the Made in USA note on nameplate] I'd guess it was made by Thermal Dynamics and sold by a Miller dealer. Did you get any manual or other paperwork with it? Have you tried any internet searching to find any information, another one, or something that looks similar and made by T.D.? Can you call that "free" 800-number?
If I had it, the first thing I'd do ( it not connected to power, of course) is open it up and look at it, hoping not to see any obvious problems. Blow out any dirt and dust; check all large connections such as to diodes/rectifiers; look for signs large capacitors are bad; measure the resistance of the power switch while moving that, check all components in the torch for wear or??. It looks either well-used, or rather abused, IMHO.

[N2 Welding]

I am guessing here that is a Miller machine with a Thermal Dynamics torch and the TD sticker is there for torch parts identification purposes and parts ordering. Did you Google the Miller number?

[ccawgc]

Miller spectrum 500 manufactured in 1990.
Go to millerwelds.com and enter the serial number and the correct owner's manual will be there for download. Trouble shooting section may help you.
Did you change the consumables when plasma stopped working?
If you changed the swirl baffle / start cartridge. This may have caused the problem.
This is a HF start plasma and a lot of these machines have shorted torch sensors.
The electrode and tip can not touch or the torch will not fire.
To fix these Thermal dynamics made a pin back kit. You press the center ring on the start cartridge all the way in then push the pink rubber pin into one of the holes.
No more than 1 pin can be used.
Turn plasma on. Check all the lights on the panel front. Ready light has to be on before torch will fire. if ready light is off, what trouble light is on.
If ready light is on, pull trigger and watch lights. what happens.
Put the start cartridge that was working back in the torch and a new electrode and tip. sere if it will fire. Try and post some pictures of the consumables and the torch head where the electrode plugs in.

[whtbaron]

We didn't alter anything, but looking at the torch tip, maybe we should have been. When we first fired it up, it took a while to warm up, but everything worked fine. Right now everything is stone dead so I will check out the Miller site to see if we can get a new switch for it first. Manuals would be a good thing, right now we have nothing, and yes, it appears to have been ridden hard.

[acourtjester]

well start with the basics and replace the on switch, I would open it up and use a meter to check the start switch for power. If you get it going don't use it until you get some new consumables, if they are available, that may be why they sold it.

[whtbaron]

There was a bag of tips etc. that came with it... I'll wait until I get a manual before I start pulling things apart. Right now it's going to have to wait in line behind the other repair jobs...

[MinnesotaDave]

Switches are easy to rule out. Just hook wires together and plug it in. If it turns on and works, switch was bad.

....using a volt meter is easier though

[ccawgc]

Not very complicated machine. Just a transformer, diodes and contactors. Contactors are controlled by the time safety pcb.
Once you can't get torch part we should be able to switch the torch for a SL60 torch.
When you are ready to work on this unit. Start a new thread in the Miller room.
What we need to know is what lights up when you first turn the power on?
Try it with no air connected and see if you get an air fault light.
Remove torch cap and see if cap light comes on and ready light is off.
Connect air and see if air fault light turns off.Down load the manual from miller, just enter the serial number to get the right one.

[whtbaron]

I'll do that.... thanks.

[whtbaron]

Good thing you gave me the Miller model name because the Acklands serial number wouldn't work. I've got the manual... one of the first things that pops up is not to cut in the gouge position because it won't get enough air.... appears we were cutting in the gouge position. I should have talked to you guys first. Apparently watching 5 mins of the 20 min Youtube video isn't enough, because that's pretty much what both my son and I did. One of the questions above about consumables got me thinking... "What did we change?" It came with a big 4 prong plug that wouldn't fit my welder outlet, so the first thing I did was rewire it with a 3 prong plug. I know we did manage to trip the breaker ( a new one) at least once so it was drawing some serious current. Before I even check the switch, I'm thinking I better open up that plug in and see if I've got a burnt wire/connection. The plot thickens...

[acourtjester]

You may end up with a very handy tool

[whtbaron]

I hope so... I really liked it while it was working... lol, but if I get it working too good, my son is going to want to take it home again...

[MinnesotaDave]

I hope so... I really liked it while it was working... lol, but if I get it working too good, my son is going to want to take it home again...

Just get in the habit of saying "still something wrong intermittently when I move it around. So I just keep it in one spot."

[whtbaron]

Hey Dave... my parents went to Bemidji on their honeymoon. Apparently it was a big trip for a Model A. I grew up seeing pics of them with Paul Bunyan and Babe. Just an insignificant aside while I put off fixing stuff yet again...

[Oldiron2]

Hey Dave... my parents went to Bemidji on their honeymoon. Apparently it was a big trip for a Model A. I grew up seeing pics of them with Paul Bunyan and Babe. Just an insignificant aside while I put off fixing stuff yet again...

Any chance that Model A is still around? If so, and if it could use some increased reliability, its engine has recently been redesigned with significant internal improvements but the exact same outside dimensions, using all stock parts except for a new block, the rods and crank. A prototype was produced, checked during assembly, installed in a car and run up a nearby mountain (Pikes Peak?), then disassembled and examined for wear, etc. Production is expected to start next year, assuming fossil fuels haven't been outlawed here yet.

If interested, the whole story can be read at ModelAEngine.com.

I have no monetary interest in the project.

[MinnesotaDave]

Hey Dave... my parents went to Bemidji on their honeymoon. Apparently it was a big trip for a Model A. I grew up seeing pics of them with Paul Bunyan and Babe. Just an insignificant aside while I put off fixing stuff yet again...

Paul and Babe are still there at the lake front

Now I've sold my home up there and moved closer to Minneapolis for work...ugghhh.....Minneapolis.....

[whtbaron]

Any chance that Model A is still around? If so, and if it could use some increased reliability, its engine has recently been redesigned with significant internal improvements but the exact same outside dimensions, using all stock parts except for a new block, the rods and crank. A prototype was produced, checked during assembly, installed in a car and run up a nearby mountain (Pikes Peak?), then disassembled and examined for wear, etc. Production is expected to start next year, assuming fossil fuels haven't been outlawed here yet.

If interested, the whole story can be read at ModelAEngine.com.

I have no monetary interest in the project.

Not that one, but the guy that ended up with it was a friend of Dad's and felt bad about it getting away on me so he gave me a sick 4 door with a broken block. Odd what an extra 50 years in the cow pasture can do to a car. I don't have any plans for a new Model A engine any time soon (probably get a newer V-8 if I ever get to it) but I am working on a 28 Whippet that I'm hoping to build a speedster body for and install a flathead 6 out of a 54 Dodge truck.

[Lis2323]

Looks like it was made by Miller with the letter in the serial number indicating year of manufacture.

The Thermal Dynamic sticker is prob just a dealer who once ran his ugly breath over it.


AFASIK Most orange Ackland welding machines were Miller. I had a push pull box and an AEAD among other stuff I can’t think of atm.


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[Lis2323]

Actually you and your son don't want that ugly old thing.

Bring it out west when you come to pick up your Idealarc. I will give it a proper burial and save you the embarrassment.


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[whtbaron]

LOL.... yea, I haven't had a chance to look at fixing his broken stuff yet, still working on mine. I did open up the 3 prong plug I put on it and it looks good, so I'll open up the top next and test the on/off switch. Hopefully we didn't fry things too badly. I've been threatening to buy one for about 20 yrs... might happen yet.