Powering up old tube

brian257
Posts: 82
Joined: Sat May 03, 2014 11:51 am

Powering up old tube

Postby brian257 » Sun Feb 04, 2018 7:31 am

I have a laser with a 100W Reci tube that has probably not been powered on in 5 years or more. Other than cleaning the optics and making sure that I have good water flow and purge the air is there anything I should know before powering up the tube. Does it need to be run at low power for any amount of time or just let it rip?

Also, I have a brand new spare tube that has never been powered up. Is there any reason to power that tube up every now and then or should I just leave it in the box until ready to use it?

Tech_Marco
Posts: 4330
Joined: Mon Jun 15, 2009 3:00 pm

Re: Powering up old tube

Postby Tech_Marco » Mon Feb 05, 2018 9:46 am

Power up the tube with low current say 4mA~5mA. Observe if any 'sparking' noise or arcing happened from the power supply or from the tube. If no gas leaking, then you shouldn't hear sparking sound. Before the tube entered stable mode, a little electric sound like 'zee zee' may be heard but it is OK once it pass over the threshold current. For Reci 80W~100W, the threshold current is about 8~9mA.

Now gradually raise current up to 10mA and the growing light inside of the tube should be stable (while plasma-like movement at the anode is totally normal, no panic). Let it run for about 5min and if no problem observed, then slowly raise up the current to 15mA and then 20mA, and 28mA(peak) step by step!

Make sure water is around 20'C, not too hot but not too cold either!

Marco

brian257
Posts: 82
Joined: Sat May 03, 2014 11:51 am

Re: Powering up old tube

Postby brian257 » Mon Feb 05, 2018 7:37 pm

Thanks Marco. I just ordered all new optics from you today. Got the DSP about a year ago, but other projects have gotten in the way and just getting back to it now. Hopefully I won't be buying a new tube and/or power supply to go with the rest. Working on a Gweiki that I got a great deal on Craigslist. Mechanical good, but replacing all the rat eaten belts and wiring, corroded mirrors, and using one of your DSPs. Also adding red dot pointer/beam splitter and beam expander.


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