Wire Sparking around Laser Tube

[Katie m Pierce]

Hello,
I have worked with full spectrum lasers but just bought a new chinese 100w laser. It has been working ok for a few weeks. Suddenly started hearing a popping sound, thought it was the beam hitting the glue spots in the wood. Then today, it started making a strange noise, I watched the back right side of the tube when I fire and it slowly lost its pinkish glow, I went around the the tube itself and had someone hit pulse, I noticed a spark coming from the wire that is around the tube. I Took some pictures, the laser is not firing, I turned it off and came to this forum for help. I have pictures, if anyone can tell me what to do next to fix this and if my tube is broken or if the wiring needs replacing or what to do. Thanks

[Mike Null]

Katie
Welcome to SMC. Why don't you post some pictures. I'm sure there'll be some help for you.

[Wilbur Harris]

Like Mike said...post some pictures. That said, your explanation of what happened leans toward a failed tube. The exact same thing happened to my 100W RECI tube.

[Dave Sheldrake]

Possibilities

• Tube is dead
• HT Connection is lose or broken
• Power supply output is set too high
• Insufficient insulation around HT wire connection
• Working atmosphere is too damp
• Bad ground connection

Lots of possibles, most likely is an 80 watt tube being over driven and sold as a 100 watt leading to the tube failing due to the over driven load and/or PSU failure. China has a big habit of overstating tube outputs, using 80 watt supplies on 80 watt tubes, running them really hot and calling them 100 watt

[Katie m Pierce]

Hi, thanks for your reply. I can see a spark coming from the wire , my friend bought the 80w and I got the 100w, there is a difference in the size of the tubes. What output should I be running it at? I'm new to these lasers. Love full spectrum but the price range was a little out of reach for me. Was hoping to make some money and upgrade later. Does anyone know if I could wrap the wire with better insulation and try again or is that a bad idea ? It's the wire on the left, red, under the tube.

Any tips on this laser is appreciated.

https://photos.app.goo.gl/vnwlUqvcxHyBAQ1W2

[Katie m Pierce]

https://photos.app.goo.gl/f56jwMGmVz7bNFSy2

[John Lifer]

As best I can see, you don't have any "extra" insulation around the red wire. Assuming it is arcing at terminal or along wire. Check first and make sure it is good connection at the tube. Mine has a length of silicone tubing (same as the water line) along the entire length of the red wire. From power supply, to the connection at the tube.

[Matt McCoy]

In the second pic, it looks like the HV wire is arcing to the tube mount. The black electrical tape is insufficient and the whole red wire should be shielded in a silicone tube insulation. I would also check to make sure the machine is grounded properly. That wiring job makes me nervous.

[John Noell]

Hi Katie, In my experience arcing due to poor insulation is a common problem on Chinese machines. Typical tape (black or coloured) is not effective at high voltages. Putting a sleeve of silicon tubing over the HT wire is a very good and effective way to insulate *most* of the wire. At the point the wire attaches to to the tube (or where the wires connect if it is the type with built-in wires), I use a tube of white goopy stuff. I have no idea what it is as the writing is 100% Chinese. It came with one of my lasers. I have been told that 100% silicone rubber works well but have no experience with it.

As Dave says, beware of tubes (and PSUs) that are sold above their "real" ('agreed') power. I've gone through enough tubes to say you are safest when staying at an absolute maximum of 85% of the amperage listed by the tube maker for your wattage tube.

[Kev Williams]

For what it's worth, I've been zapped by silicone spark plug wires probably half a dozen times in my life, last time was while pulling the trans dipstick in the wife's Mustang, my elbow touched the #3 wire, yow! Wires had probably 1000 miles on 'em... I've also watched silicone plug wires arc to heater core water hoses 1/4" away from each other, due to the carbon black in the rubber...

Just sayin'

[Katie m Pierce]

alright, so I bought some high voltage tape, now after reading all of this I am going to try what was suggested here, my question is, is the wire fried? The tube is no longer working, when I hit pulse, it sparks out of the wire as shown above, I definitely see black where it has been doing this, does that mean I need to replace this wire, and is the damage done, will I need a new tube or will fixing the insulation around this wire be sufficient you think ?

[Katie m Pierce]

Update, I took off all insulation to see if the wire is shot. I am attaching the image . There is definitely a break in the wire, help! What do I do from here? How did I fix this wire?

[Katie m Pierce]

Pictures
https://photos.app.goo.gl/J7RAVPUTGiVzTaYg1

[Bill George]

Update, I took off all insulation to see if the wire is shot. I am attaching the image . There is definitely a break in the wire, help! What do I do from here? How did I fix this wire?

The wire is toast and since its cheaper than the tube, (IF it was bad) replace the entire wire first. If you can find a auto parts store that carries copper core silicone insulated spark plug wire buy and replace. Do not use carbon core wire, if the kid behind the counter does not know, find an old fashion auto parts store or maybe a NAPA store. Or you can order online from a place that sells laser machine parts lightobject dot com is where I get my stuff. http://www.lightobject.com/High-Volt...pply-P748.aspx

FYI once a High Voltage carbon track is on a wire or device it will be arcing worse, like yours did. There is no high voltage wire tape that I know of that will insulate 20,000 to 30,000 volts, none that a consumer can buy anyway.

When you replace that wire slide some of that clear silicone tubing over the entire length and route away from metal and water tubes.

[Dave Sheldrake]

Get a proper HT wire connector as well, that bundle of wire joint is a recipe for arcing from the get go.

htconnex.jpg