Problems after running new tube for a few hours today

[bberzinskas]

Greetings!

I recently upgraded to the SP 45W tube and a matching power supply. I finally got some time to get it running in my machine and managed to cut out a few things. I ran the machine at about 14mw with water ~75degrees. After a few hours of intermittent work, I heard a distinct buzz and the laser stopped lazing!

Where do I start?

[Techgraphix]

Although the traces of arcing vary from invisible to obvious, try to find where the arcing took place.. If it is the wiring (HV-wire and connector) to the frame, make this distance a bit larger. Check the insulation around the lasertube's connection, inside the HV-powersupply connector etc etc.. If the buzz was from inside the HV-supply you will probably have some warranty.. You have to break the seel to peek inside.. Be carefull: hazardous voltages can occur on charged components.. Arcing can occur insid the HV-transformers but also on weak or broken soldering on the PrintedCircuitBoard (PCB) especially around heavy components like the transformers and coolingplates..
For the HV-wiring: this must be at least 2 cm (~1 inch) from any metal framepart or any other wire... Better more..
Else, remove that buzzing bee

Kees

[bberzinskas]

I'll check around the PSU / Wiring today. The distance from the HV wire to chassis was a few inches, and I had a good bit of silicone tubing running from the glass nipple down, so I don't think it was there. Is there a definiative way to rule out PSU or tube? This PSU doesn't have a test button like my old one. The fan does come on, but I imagine its an AC fan run from the mains?

[bberzinskas]

I'd also like to add, that the beam didn't seem as "stable" as I thought it should, and i saw a lot of "jumping" of the light column inside the tube, partiuclarly towards the front end.

[bberzinskas]

Checked around the chassis, no visible signs of arcing. Looked at the tube with a flashlight, nothing terribly interesting there. Does cracking the psu void the warranty? Is there anyway to test it w/o the tube to verify its not say opto's or something? Are there any indicator lights inside the psu that might be helpful?

[Tech_Marco]

How did you drive the LPSU? By DSP card or ??

To test the LPUS without controller, do this:

1) Connect WP to Gnd
2) Connect +5V to IN
3) Connect the TL to Gnd (note: I suggest to add a push button in between the TL & Gnd because once you bridge these two terminals, the LPSU will fire in full power!)

Do the test in quick because over current is not doing good to the tube.

Please update the result. I'm in China, otherwise I can chat with you. But no worry, there is warranty cover and we will replace either item for you if it is defective!


Marco

[Tech_Marco]

BTW, the plasma movement inside the tube is normal. As long as not running small and rapidly, slow movement is normal once the tube passed triggering point and at operation point. Don't worry about it. Usually, you will see the pink light running unstable at 4mA or lower for small tube. For Reci 100W or 130W, they need 8~10mA to reach stable point. Once a tube entered stable zone, the ligh (inside the tube) looks very stable except for the laser head, the metal barrel. You will see beam movement around a bit


Marco

[bberzinskas]

I'm controlling it with an Arduino running BuildLog Marlin (reprap) firmware. It uses 2 pins (fire and pwm for intensity).

I tried the test by setting up a spare connector to jumper the appropriate pins around. Turned it on, no signs of life.

[Tech_Marco]

Open the case and check the fuse see if it got burned. If the fan is running, chance is that the PSU is damaged. The LPSU need three wires to run: Gnd, PWM(In), and TTL (TL). It has to be 0 to 5V signal.


Marco

[bberzinskas]

The fuse is fine, visually and w/ continuity test.

I did however notice this oddity, presumably from the HV section. It looks like a crack and a bit of thread or melted plastic sticking out the side of what i can only imagine is the HV tranformer?

[bberzinskas]

just to clarify. the white string you see is actually coming out of the cracked white plastic box above the resistor (which i think is the hv transformer).. do i need to RMA this?

[Tech_Marco]

It seems that you have the output shorted and blew out the power transistors and other components. I'm repairing it now. You may want to make sure firmly connection once we return the LPSU to you, but don't do soldering on the pin


Marco

[bberzinskas]

Marco, I received the PSU and all is good! I also used a copper terminal used for ground wires to keep the connections solid. The silicone tubing also fits over these, so i'm confident i'll have a good connection now.. Heres a link to what I used, the one i found was smaller then pictured, but people will get the idea:

https://img0.fastenal.com/productimages/0706961.jpg

[Tech_Marco]

That looks a good solution for most folks who had trouble of making HV connection. Where did you get it from?


Marco

[bberzinskas]

just picked them up in the electrical section at the hardware store. $0.79 each, TOTALLY WORTH IT!