L-ON line produces only 1.9V of voltage while PSU is connected. Should I replace the controller?

[ednisley]

@Ndx

dumb laser connector

Yeah, that looks dumb, all right.

These previous discussions may forestall killing yourself by making common (mis-)assumptions:

Thermal glue for tube wire?

Hello all. I have been trying to find an answer for this assumingly easy question, but cant seem to. I need to reglue this wire to the tube and dont know what kind of glue/paste this would be. I have been seraching “co2 laser + thermal glue” , “co2 laser + thermal paste” , etc, with versions of HT wire, ceramic block, multiple types of terms but cant seem to find an answer. Can anybody give me an answer, thank you in advance. [20241231_101129]

Laser HV wire arcing and hissing despite insulation

Hi everyone! After you all helped me solve my previous laser problems: i got a new cloudray tube and power supply and it was working terrifically! but one morning we turned it on and the laser wasn’t firing, and instead making a loud arcing/popping sound. Nothing physically changed or moved around between when it was working and not. Just like 12 hours had gone by. I looked in the back and saw there were sparks arcing from the HV laser connector wire and the bed. i recorded a couple videos…

[MikeyH (Mike Hembrey)]

@Ndx

and isolating it with a car gasket sealant.

Did you miss that part about killing yourself?

Car sealant is not rated for the voltage (15KV) you are dealing with here. In fact, if it is black it may be full of carbon. You need high voltage RTV silicone sealant.

You also need to make a secure mechanical connection to the post, not just wrap it. That leads to an intermittent connection due to wire oxidation. Copper is a great conductor. Copper oxide is a great insulator..

Not enough time to do it right, but plenty of time to do it over?

[Ndx (Norvydas)]

Dear @ednisley and @MikeyH thank you for safety updates.

Regarding sealant I have read that it is needed to use 703 silicone or RTV car gasket sealant. Maybe I paid too less attention if I am using RTV sealant or any other type of car gasket sealant and it is my fault. Since I am having TC-703 which came with machine I will use only this material to ensure connection safety.

However, regarding soldering I have made some research before and I found that tight wire twisting

How do I connect wires when I replace my laser tube? - #3 by renegadeltd - Lasers - Maker Forums says:
Do not solder!
Forces on the post in the tube can crack it.

Don's Laser Things: K40 Laser Tube Specifications, Maintenance, Failure & Replacement says:

• Your anode wire may be twisted, screwed or soldered on the anode pin.
• Remove or re-terminate the old anode wire.
• Replace the anode wire in the same way it was connected, twist, solder or screw.

FSL also offers twisting without soldering, they just adding additional tape at 5:20 : https://www.youtube.com/watch?v=YBtMBGnp5pw

However back to topic. new Ruida mainboard came. And results are the same 1.9V… while PSU is connected.

Actually this was expected so there is 100% clear that both LPSs are faulty. Also I will use the new motherboard only because it could be that issues were caused by faulty old controler

I have ordered the new LPS (more expensive black one). However there is an open questinion why the new LPS broke after several seconds of engraving at the same way as old one. It looks like some component in the machine don’t like power spikes during engraving process and it leads to broken LPS. I am affraid that the third LPS could break in the same way too Please help me to not screw the third LPS because it could be that root cause is still active:

• Maybe the old controller was faulty, had some voltage spikes during engraving and everything will be fine now?
• Maybe the 24V PSU is faulty and causes signal voltage spikes during engraving process which could lead into failure?
• Maybe the tube is faulty and causes this issue? It is new but maybe defective - I have replaced it and had some cutting jobs for two days. When I have tried the first engraving job - the old LPS died. When I tried to engrave once again with second LPS it died too. It is not the first time I have replaced tube and this time I have done everything the same as I done it before…
• Maybe the any connector in the machine, wire or small minor component (such as mAmpermeter, etc) could be faulty and cause death of LPS? In this case it looks like it is impossible to find a faulty part at least everything I have checked looks decent.
• Any possible reason I haven’t mentioned yet?

[ednisley]

@Ndx

703 silicone or RTV car gasket sealant

Neither of those are rated for high-voltage insulation applications. Worse, if the gunk smells like vinegar while curing, the acetic acid it exudes will rot any nearby metallic objects.

@Ndx

• something like short circuit sound
• why the new LPS broke after several seconds

If the high-voltage anode wiring was improperly insulated, the power supply arced to adjacent wires or the machine frame. Whether that killed the controller, the power supply, or other circuitry cannot be determined, but any and all of those seem plausible.

@Ndx

both LPSs are faulty

At this point I’ve lost track of what components / settings / connections are in play, so I will have nothing further to add.