I recently bought a used Crossfire with a Razorweld 45 for the occasional flat-plate needs of the shop.
I have gone through the THC wiring and verified that at least it looks like everyone is set up right. I then went to do the THC rest. It passes the passive test showing 0-0.2V, but when it goes to the active test where I need to confirm I see an arc fire, nada happens. I hear a click, like a relay in the Razorweld, but no fire.
So I went to verify the voltage across the positive and negative of the voltage divider. I set a 8" straight cut with the head still an inch above the work surface, torch on, pressed go and measured the DC voltage and got nothing.
So I’m not really sure what to troubleshoot next as presumably this is a Plasma unit issue and not a THC issue if I’m not getting voltage out of the plasma unit.
The firing of the torch has nothing to do with the THC wiring.
Do you have the torch on/off wire plugged in to the razorweld and the electronics enclosure?
If you hear the relay click, but the torch doesn’t fire, switch the wires at the front if the plasma cutter. This assumes that you have adequate air pressure supplied to the plasma.
Those connectors on the front if the razorweld have been switched back and forth so many times that razorweld doesn’t even know which is which.
Can you elaborate on switching the wires? Here is what my front looks like. I just have ground and the machine torch input. Do you mean having to switch wires inside the torch lead cable? I believe I have enough air pressure. It’s running off the same one my CNC uses (not at the same time) which is set at 100psi, and I can hear the plasma bleeding off excess.
Actually, blowing up my photo it looks like those torch leads and ground will swap ports. I see a + molded into the plastic where the negative currently is. I guess I made an assumption when the torch lead fit that’s where it was meant to go. If that fixes it I’ll feel stupid, and deservedly so.
Not the torch leads. They won’t switch anyway, though.
I’m taking about the two small ports on the lower right. One of those is for firing the torch and the other is for divided voltage.
It looks like you have a wire coming out of the case, so maybe the previous owner wired the divided voltage inside the machine.
In any event, one of the two ports is the torch on/off port. The other end of that should be connected to where it says torch on/off on the electronics enclosure. If the torch doesn’t fire from the port that it’s currently plugged into, switch it to the other port next to it in the front of the plasma cutter.
This is what the two smaller ports look like. The lead going to the THC is two-prong, and has the red tape from the previous owner so I assumed that’s where it’s meant to go. The two-prong plug will go into the 4-prong in various orientations, but hard to imaging that’s correct.
Was the torch already mounted in the carriage for the Z axis or did you have to put that on?
The Razorweld torches are sensitive to the clamping pressure of the torch mount and you can bind up the internals of the torch if it is too tight thus causing it not to fire.
That’s an older version of the Razorweld. The ones that come from Langmuir have 2 identical ports on the front.
The 4 pin port is the one that turns the torch on and off, so the previous owner must have connected the torch on/off wires inside the machine.
Where do you have the wire that comes out of the case plugged in? It goes in the torch on/off port on the front of the electronics control box on the table.
Edit: I just looked at the picture you posted again. You have the torch on/off cable plugged into the VIM box. That’s your problem. That cable gets plugged into the box that is attached to the table, in the port labeled “torch on/off”.
Great, thanks! I now have the torch firing. Still no voltage reading coming from the 2-pin on the lower right. THC testing fails the live test because it does not sense any voltage when firing.
I tried reading it with a voltmeter while telling it to fire/cut a straight line but got 0v there as well. So it appears the THC box isn’t getting anything in the red cable. I guess the next step is to open up the cutter and see what is going on inside?
Check for voltage at the pins on that 2 pin port. It should be less than 3v DC.
Just to make sure you have the cable connected to the VIM, the cable from the plasma guess to DIV input and the cable from the DIV output goes to the THC port on the control box.
When I check that 2-pin for voltage I get 0, whether it’s idle or firing. That cable goes to the input of the VIM, and then the output (yellow) goes to THC.
I have some cables coming to tap into raw voltage, just to see if it’s possible the volt divider port isn’t working, or if this model, since not purchased from Lanmuir presumably, has a 20:1 split instead of the 50:1.
That’s possible, but the previous owner must have been using it that way.
You may want to take the cover off and make sure the wires are connected to the back of the port. You’ll have to remove the cover to hook up to raw voltage anyway.
Yeah I’ll take a look. I’m presuming the previous owner used THC successfully, but that said I don’t know if they did or not. I believe the system is usable as I have it now minus THC. But if I see anything loose I’ll dig deeper. Just wanted the raw cables in case since it’ll be open anyways.
I just saw a post that said if you didn’t buy the Razor from Languir they have a different motherboard, and then your comment about how the razors from Langmuir would have had two, two-pin ports instead of a 2 and 4.
