View Full Version : blown tube or bad power supply?

James Neathery
07-22-2017, 9:08 PM
last night i was doing a test cut on my chinese 60w c02. this thing has been a nightmare from the word go, but after 4 or 5 tries aligning it i finally got it working. last night i was running a job and the laser suddenly stopped firing. the gantry kept moving as normal, just no cuts. i have tested everything from the ac inlet to all the switches. the psu is getting power. the light in on and the fan is turning, but i don't have the equipment to test the output. if it were a faulty tube, wouldn't the power decline somewhat gradually over time?
i was running the cooling unit of course, everything is set up properly. like i said, lasr was firing one second, and not firing the next.
when i hit the pulse button it beeps but of course no laser pulse. i held a piece of paper in front of the window and it did not so much as darken.
has anyone had a similar experience? what was the problem if so?

mitch stephens
07-22-2017, 9:30 PM
Check the water flow switch. It will not fire if its not working

Rich Harman
07-22-2017, 9:34 PM
Also check fuses.

James Neathery
07-22-2017, 9:59 PM
all fuses i can see are fine. i took apart the psu and there is a small fuse on it, it's fine too. no scorching on the psu i can see.

James Neathery
07-22-2017, 10:00 PM
i haven't done that. where is it located?

Doug Fisher
07-22-2017, 10:21 PM
Is there a door interlock switch on your unit? Sometimes those go bad fairly quick on these lasers. Not sure if that would give you an error on your controller panel or not.

When you do a test fire, do you get any pink glow out of your tube? If you have an ammeter on your laser, do you get any movement from the needle?

Matt McCoy
07-22-2017, 10:27 PM
If the water flow switch is OK, then it sounds like power supply.

James Neathery
07-22-2017, 10:41 PM
no door interlock, i've run it tons with the door open doing alignment. no glow i can see but i have never seen any glow. there are no ammeters or otherwise on the machine to show laser output that i am aware of, unless the user control panel has one, in which case i haven't checked that out.

mitch stephens
07-23-2017, 7:20 AM
i haven't done that. where is it located?

If you are talking about the water pressure switch it should be in one of the water lines, find it and just bypass it to see if it fires then

Bill George
07-23-2017, 4:09 PM
If you are talking about the water pressure switch it should be in one of the water lines, find it and just bypass it to see if it fires then
Basics, do you have water flow and how did you check? You could have a door interlock switch and all the times you had the door open it was jammed showing it was closed, and now its un-jammed and stopped the laser from firing. Water switch or flow switch someplace in the cooling circuit, door switch someplace on the door or frame. Never had a machine without either one. In fact I think FDA approval requires.

John Lifer
07-23-2017, 7:07 PM
No door switch on any of my doors, andi dont haave normal water switch. Cut off in rdworks and controller. But i think one does exist somewhere as machine wont fire unless water is on.....just haven't found it, internal to the cw5000?

Kev Williams
07-23-2017, 7:40 PM
On the side of my Triumph between the generic power switch and generic light switch, is a generic "laser" switch. Haven't seen many set up like this, very convenient for doing 'dry runs' to make sure the laser head is going where you think it's going with the laser off... It took me a while to get used to IT being the reason my laser wasn't firing ;) --

Your's may or may not have a similar switch?

Yours SHOULD have a smack-down E-stop button-- Check it too, as some of them only shut off the laser and not the whole machine...

Rich Harman
07-23-2017, 8:12 PM
Have you verified that there is no arcing? If you are in noisy environment you may not hear it. When my tube failed it arced to the water inlet causing the silicone tubing to catch fire. There could also be arcing somewhere before the tube.

James Neathery
07-24-2017, 3:01 AM
thanks all for these suggestions, i have tracked down the problem after trying all these ideas, it is definitely the power supply. after defeating or bypassing all interlocks and safety devices, i tried putting the laser tube leads close to each other on a piece of wood (suggestion from the laser vendor, lol) and tried pulsing the laser. there is no spark at all. the company is offering me a 200 dollar refund since they don't have any in stock. there are other places that have the exact ones for 120-150 so i am taking them up on it.