I have not yet test fired the laser at max because my ground is not properly installed. I have a dedicated ground cable in the workshop that goes outside and to a rod 6ft in the dirt. But, while I have it upstairs to repair it, I’m just relying on the AC ground to test at low power, since my dedicated ground cable won’t reach up here.
I’ll go ahead and give it a blast at 100%, I see plenty of K40 users using their lasers regularly, relying only on the AC ground on the wall socket. I’m sure I’ll be fine. Soon as the wifey takes these kids off my hands I’m going to fire it up again and test fire at 100% while noting the analog mA reading.
Ok I’ve got some values documented on video. I also installed a DVM to the ammeter to show 0-5V display. There does seem to be a significant loss in power because previously at 100% power on the dial, the ammeter would be maxed out. Now it’s only reaching 20mA even with the pot at 100%… here’s another follow-up video… https://youtu.be/ua5nEHlPmAY
Ok… so you don’t want any more than 15-18mA to the tube as it will degrade the life of it. your old PSU was probably mis calibrated and allowed the max mA to go much higher than it should have. anyway… ok you have plenty of power now. The fact that you have 0 emission out of the OC is the exact same issue that the other user has on the group… You have outruled a power problem. there is something wonky with your laser tube.
The old PSU could have very well been miscalibrated, as it really buried that needle a lot more than what I’ve seen from other k40 users on youtube.
I have an old tube that still worked, but it’s a real “bottom of the barrel” cheap ebay tube with many hours on it. Tonight I will install it just to see what happens.
Needless to say, I’ll be in the market for a tube ASAP. Those RECI tubes look interesting but I see many people having problems with the lens/metal cap mechanism.
I can’t afford anything fancy right this very moment, but something that will work for now. I want to stay away from ebay as both tubes I bought from ebay over the last year arrived broken.
Light Object is the only thing coming to mind right now, or I’ll be happy to work something out if you’d like to sell one of your spares. You have a good reputation here, and I have a paypal acct
Yes if you get a chance hook up the old tube and give it a whirl. even if it’s weak, if it emits some radiation and burns paper you know where you stand.
Well,Thanks for the flowers … I try to help when I can… if that’s the reputation you heard about then I’m grateful…
Interestingly enough, I have a local guy interested in my spares and says he’ll be by to look them over this friday… If anything falls through with that I’ll set one aside for you… I was somewhat against shipping them due to their fragile nature but if you get stuck and he doesn’t take them I’d make the exception.
Yea, I hear you on the shipping risks, these tubes seem to arrive at their destinations broken more often than not. Much better off with a local pick up and avoid that strong potential of damage.
Well, hang tight until at least friday on pulling the trigger on an LO tube. Good luck with your old haggard tube… If this guy fails to come through, I’d be fine with wrapping one up safely for you.
We’ll just put insurance on it so if it gets broken it’s covered.
Sounds good to me. I installed that tube last night and fired it up. Took about 10 mins adjusting the mirrors and it was cutting. So there was certainly something going on with the other tube, even though it was producing a nice, steady beam of plasma… Perhaps I’ll try and edit those videos together and film another now that the problem is solved. Maybe it will save some trouble for others in the future seeing as how these problems seem common with these K40’s.
