View Full Version : Need help diagnosing Shenhui problem

John Noell
11-30-2015, 6:56 PM
First, the power dropped, rather suddenly, to about 60% of what it was. The EFR tube is only eight months or so old with not a lot of use. I checked alignment and fine tuned it but no help. So, I put a new RECI tube in and was pulsing it to check and adjust alignment. After about 10-12 pulses the RECI power supply starts beeping and says "Short circuit - analysis: high voltage." Where the high voltage line attaches to the tube the wire looked a bit weak but there were no signs (or sounds) of arcing anywhere. Just to be safe, I resoldered and reattached the high voltage line. After I started back on checking the alignment, again, after 10-12 pulses, the alarm went off again.

Might the power drop have been due to a bad PSU? I do have the original (cheap) PSU that came with the laser so I can put it back in and test, but it does not have any alarms or diagnostic output like the RECI PSU.

Any thoughts on the source of the problem would be appreciated. (Long ago I checked all the connections and tightened everything but have done so lately.)

Dave Sheldrake
11-30-2015, 7:06 PM
PSU sounds shot John, I'd suggest something inside is leaking (the intelli supplies definition of the alarm you are getting is HT leak) there isn't always an arc, sometimes it's a quiet hiss that doesn't notice till the part leaking catches fire.

I'd swap back to the older supply and see what happens

John Noell
12-01-2015, 11:44 AM
Thanks Dave. That is what I'll try today. I appreciate your advice.

Bill George
12-01-2015, 5:52 PM
John, is your power coming from the mains or generators that supply the whole island or are you on your own solar or wind? Seems like your having a lot of laser machine problems.

John Noell
12-02-2015, 11:19 AM
We have generators that supply the whole island. And to make things worse, my house also is at the end of a spur, so I am far from the last transformer and highly subject to neighbor-caused fluctuations. The power is very flaky with frequent complete outages. I used to use a voltage regulator and plan to start again.

Bill George
12-02-2015, 5:19 PM
A regulator can only do so much, if your way down on voltage because of a heavy load, regulator can not make up the voltage drop. You would be better off with a heavy duty UPS system with batteries supplying the power when needed. Read expensive. Or just use the grid for the house and put in a solar system and batteries and the required invertors for your business, read even more money.

Yes, I did read online your weather, looks to be about the same all year around.

David Somers
12-02-2015, 5:55 PM

Not sure if this is a valid thought. But rather than a UPS or Solar system that is big enough to cover your gear how about a generator of your own, perhaps still with a voltage regulator?

Or, depending on the costs of these items and the cost of replacement parts perhaps you just need to have spares of all your components. Cover your system with a VR to be safe since that doesn't cost that much, but just stock up on spares? You would have to sit down with a sharp pencil and see where the balance is. Obviously you need to factor in the degree to which this is a "fun machine" versus a business tool.

Or just move here to Seattle! Our snorkeling is a bit chilly, but I had a few Meyers Lemons on our little pot bound tree this summer, and still have roses blooming. Not quite Fijian climate...but give us a few years and who knows???? <grin>

John Noell
12-12-2015, 11:47 AM
For the relative costs, given it is for hobby use, and that down time is annoying but not really costly, I have figured spares are the best way to go. Dave, thanks for the suggestion I move to a place where I could stand out in the rain and cold (and freeze to death) but I'll just tough it out here, lounging in the sunshine and balmy breezes.