Ebay 50W laser problems

[Jeff Body]

I need some help and verification please.


I have a 50W ebay laser. It's the big blue one that's similar or the same as a SH-350.


I've been using it all weekend but tonight things went very VERY wrong. I was engraving a glass when all of a sudden the laser stopped engraving. About 5-10 sec later I heard the worst noise ever. I knew right off the bat the laser was arcing. I shut everything down with the emergency stop button. The FIRST thing I checked was the water pump and it's flowing perfectly fine. I have an active 1/4hp chiller that was working properly also maintaining the water at 20-21*C.


I've completely gone over the tube and I can't find a single break over the whole thing. I've checked the HV wire and it's completely fine also. Well I needed to verify that it was indeed arcing because I didn't actually see anything spark. After triple checking everything I powered everything up and I tested the laser using the pulse and sure enough the laser arced right under the HV side of the tube.


Now what do I do?


I can't find anything wrong with the laser tube. The ONLY thing I noticed was some condensation on the hoses because the water was too cold.


After raising the temp alittle bit and waiting for the condensation to completely evaporate I decided to do another test and now I get NOTHING from the laser. Nothing when I push the pulse button and nothing when I push the test button on the power supply.


Are there any more checks I can do?
Is the tube and power supply gone?


Thanks for listening.

[Rich Harman]

Is the tube and power supply gone?

Sounds like the tube is bad. Power supply may be fine. If you are doing this for a source of income it would be a good idea to have some spares on hand. When my new 130W tube failed it was very handy to be able to swap back in my 80W so that I could keep working while waiting for a replacement.

[Jerome Stanek]

can you put a meter on the tube to check it. Here is a link on how to do that

http://www.instructables.com/id/How-to-test-and-set-a-Chinese-China-made-CO2-Laser/

[Shawn Morris]

If it did arc, you may need to hit the reset button on your power supply. The one on my SH-350 tripped once when i had arcing due to insulating material that had come loose.

[Bill George]

With the power off and disconnected trace that big thick red wire from the PS back to the tube to see if you can find the source of the arcing. Sometimes it will be routed right next to some steel or the connection to the tube may be the problem. I know about the PS fuse but Shawn says Reset button, check that first.

[Jeff Body]

Where would I find this reset button?

[Shawn Morris]

Where would I find this reset button?

Here's my power supply, yours may be different. Where in Florida are you?

[Jeff Body]

Mine looks different.

I live in Tavares which is about 45min north of Orlando.

[Shawn Morris]

I believe yours is quite a bit newer than mine. I also have the other controller RDLC320A in mine. I'm in Lake Mary.

[Ron Gosnell]

You say it arced right under the tube.
Carefully check the hv connection at the tube. That can be a weak link and a spot for problems to occur.
Some machines are soldered at the connection, some are twisted, and some have some kind of clamp.
Be careful though, I read where it's pretty fragile at that connection.

Gozzie

[Walt Langhans]

In my humble opinion you should take a methodical and logical approach else you going to probably end up confusing yourself and possible missing something.

If you think it's the tube then check it like Jerome said. If you get power (ie reading on the volt meter) and no laser, then it's the tube. If there is no reading on the voltmeter then you need to check the power supply.

First thing to check on the power supply is the power in, you can do this with a volt meter.

If you DONT have power, then you need to check back to your emergency switch (I've had them go bad) and from there back to your fuse that should be some where near your receptacle.

If you DO have power, there is probably a fuse inside of the power supply. Only problem is that your going to have to take the power supply apart to get at. If that fuse is still good, then it's your power supply.

best of luck!

[Jeff Body]

can you put a meter on the tube to check it. Here is a link on how to do that

http://www.instructables.com/id/How-to-test-and-set-a-Chinese-China-made-CO2-Laser/

Aright,,,,,,,, I did this and got NOTHING.


I believe yours is quite a bit newer than mine. I also have the other controller RDLC320A in mine. I'm in Lake Mary.

What's up neighbor.


In my humble opinion you should take a methodical and logical approach else you going to probably end up confusing yourself and possible missing something.

If you think it's the tube then check it like Jerome said. If you get power (ie reading on the volt meter) and no laser, then it's the tube. If there is no reading on the voltmeter then you need to check the power supply.

First thing to check on the power supply is the power in, you can do this with a volt meter.

If you DONT have power, then you need to check back to your emergency switch (I've had them go bad) and from there back to your fuse that should be some where near your receptacle.

If you DO have power, there is probably a fuse inside of the power supply. Only problem is that your going to have to take the power supply apart to get at. If that fuse is still good, then it's your power supply.

best of luck!

Well I've checked everything. I've got power going in and nothing coming out. Used a meter on the (-) wire and there's no juice flowing now. I've dissected the the terminal ends and they were properly sealed and completely covered in silicon. I've taken apart the power supply and checked the fuse and it's good. I'm examined the tube and can't find anything unusual.
I'm kind of at a loss here. I'm guessing the tube and power supply are gone.

What can I do from here other then buy a new tube and power supply?
The other question is what do I buy?
From LightObject.com
I can get a 1000mm 45W tube and power supply for about $500 OR
I can upgrade to a 60W tube and power supply for $700.

What do I have to look forward to if I end up going with a 60W? Is it worth the extra $200?

I could really use alittle guidance here.

Thanks

[Jerome Stanek]

Did you get the big green resister with your machine

[Bill George]

My guess no mounted mA meter, no green resistor. On tube and power supply replacement, you need to measure and see how much room you have for the new tube. LightObject sells tubes that are rated at true wattage. My other guess you had a lower rated and shorter tube that was overdriven to get the 50 watts. This has been discussed many times on this Forum.

[Jeff Body]

My guess no mounted mA meter, no green resistor. On tube and power supply replacement, you need to measure and see how much room you have for the new tube. LightObject sells tubes that are rated at true wattage. My other guess you had a lower rated and shorter tube that was overdriven to get the 50 watts. This has been discussed many times on this Forum.


You are correct........ No mA meter and No resistor.

My laser came with a block off plate that I can remove to fit a longer laser. The Stock laser tube that was in it was 850mm. Judging by the lengths on Lightobject's web site this would equal a 40W laser. This is no big surprise. I knew from the beginning that these lasers come with a smaller laser tube. That's one reason why I never went over 60% power.
Since I'm at a complete loss and I've exhausted any other tests that I could think of I have decided that the only option I had was to purchase a new laser tube and power supply. Worst case I'll have an extra of something to keep around.
I had the option of going up to a 1000mm 45W tube or making a big step up to a 60W. With this I also decided to upgrade to a 60W 1250mm laser tube and a matching power supply. I'll have to remove the block off plate and fabricate a cover but that's not a big deal for me.

No one presented any cons as to why I shouldn't step up to a 60W and I'm the type of person if I'm going to have to replace something I might as well upgrade.

[Bill George]

LightObject also sells mA meters, they are less than $20 as I recall and they are installed in the Negative lead going to the tube. Since the software adjustment values are sometimes not correct a meter is the only way to tell for sure.

[Jerome Stanek]

I picked up an ma meter and installed it in my laser just to be sure I don't over drive the tube. It was a piece of cake to install. I have to keep my software set at 85% or less for my tube

[Jeff Body]

LightObject also sells mA meters, they are less than $20 as I recall and they are installed in the Negative lead going to the tube. Since the software adjustment values are sometimes not correct a meter is the only way to tell for sure.

Funny you should mention this because it just so happens that a 30mA meter jumped into my cart as I was buying the laser tube and power supply.
Great minds think alike.