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ArcticMyst Security by Avery

Head arrived - now up and lasing!

Spooky

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Re: Head arrived - new question (problem?)

Well the optimal cfm rating is for its standard output level. (What the tube is rated) if you run it at a higher current then you'll need more nominal airflow or you'll stress the tube. Running it at low current us recommended anyway though to increase the tube life

Tube as in output diameter of the fan UK :) a 195cfm fan that is 4" in diameter flow characteristics change when it's necked down to / run through a 3 inch output. The drop is quite a bit :)

cheers

Dave
 





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That concerns me... one line at idle usually indicates that the laser is nearing end of life... I may be wrong, but that's what I think. My ALC 60X is also getting to close to end of life, it gives barely 2 lines at idle, then 7 lines all shoot in pretty quickly as you turn up the current, and lastly the 8th line. My Uniphase gives 5 lines at idle, 6 lines when you turn up the power a bit (it's in mid life condition)...

Glad you got it working though :beer: enjoy
 
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My laser is a 30 mW SL 488. The fan is a
NMB 5915PC-12T-B30 rated 212 CFM.
HMike
 
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That concerns me... one line at idle usually indicates that the laser is nearing end of life... I may be wrong, but that's what I think. My ALC 60X is also getting to close to end of life, it gives barely 2 lines at idle, then 7 lines all shoot in pretty quickly as you turn up the current, and lastly the 8th line. My Uniphase gives 5 lines at idle, 6 lines when you turn up the power a bit (it's in mid life condition)...

Glad you got it working though :beer: enjoy

I don't think it is. Unless this tube was severely abused it's almost 10 years younger than my other tube (1996 vs 2005). I don't see an hours counter anywhere so I can't be sure though. I still suspect it has high tube pressure based on how hard it was to get started yesterday. It's just about finished with a three hour burn and I plan on giving it several more long burns over the next few days just to be safe.


I slowly ramped up the current to see what lines I'd get and ended up with this:

Current Lines
3.98 (idle) 1
4.0 2
5.0 3 (faint)
5.1 4
5.35 5
7.7 6 (faint)
8 6


At full power, 10.5A, it was putting out almost 38mw. Not bad for a 10mw tube. Even if it is an EOL tube to get a fully working system (sans remote though) for just under $210 is a steal IMO. The only thing that sucks about it is unlike my rectangular head that has an umbilical that's a good 5-6 feet long the one on this head is all of 2-3 feet which makes positioning the head a pain.
 
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Interesting. I could very well be wrong, I'm no expert with Argons after all :p it's just my hunch. Not a bad deal :beer: glad you got it going

I'm not familiar with cylindrical heads, is it difficult to disassemble? If you not you could try measuring the voltage drop on the tube as a rough estimate on tube life
 
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If it's still outputting 4x it's normal output I'd guess it's fairly healthy. From what I'm told, unlike the alc 60x heads, the uniphase lasers are tough. It does sound to me also that it's a moderately high tube pressure. Though power supplies wear down a bit too. I'd run it at idle for a couple hours then up it to mid power for short bit to do a bit of cleanup and wake up the electrolytics in the supply. If you've already had a few long burns it's probably not too bad. You're somewhat over the hill once you get it going.
 
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I see. In that case, a very nice snag :beer:

I'd run it medium current for a few hours then let it rest for the day, fire it up again the next day at medium low current for a few hours, and then repeat the cycle at medium low current for the next few days. If that doesn't work and you aren't mindful of burning a bit of life, try baking your argon at full current for an hour or two, that would give you a big performance boost if your argon really does have high pressure.

And yes once you get it lit and going you're well over the hill, personal experience says :p
 
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Hmm. I'm almost positive the lack of lines at idle is due to high pressure because unlike last night where it fired on the first tick tonight it wouldn't start at all and AFAIK that's a tell tale sign of high tube pressure. I used Hemlock_Mike's trick of letting the filament warn up warm up for about 5-6 minutes without the fan going and it fired after about 8 ticks. Ramped it up to 6A where I'll let it run for probably 90 minutes before going back to idle then shutdown for the night. Tomorrow it'll probably get a similar workout but ramp it up to 7-8A for a good hour or so before going back down.


I hadn't thought about PSUs as they age. The one I'm using now is well exercised as it's the one I use with my
 
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Yeah they dry up after a while if they're not used. Also make sure you're at max current starting the tube. It puts less risk to the psu for surges because the pass bank is wide open.
 
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This tube is doing it's best to annoy me. Last night it fired after about 5 ticks but tonight it's back to nit wanting to start. Even after letting it warm up first it ticked a good 10-12 times. I was going to give it a 90 minute workout at 8.5A tonight as a followup to the 90 minutes at 7A last night but the heat that this thing is putting off is making the room a bit toasty.

I was hoping the PSU I ordered would be here before the weekend but it looks like it'll be next week before I can fire both argons at once provided of course I can find a way to power both PSUs without tripping breakers.

edit: also noticed I'm missing a line tonight.
 
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This is beginning to sound strange... usually if it's a high pressure problem the ticking issue goes away after two or three runs... you may have a slight PSU problem somewhere?
 
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Yeah it's kinda odd. I've run it every night for the last five for at least 2 hours a night which should take care of the tube pressure. I have a different PSU on the way but it won't get here until Monday.
 
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I would say wait until your PSU comes in, it doesn't sound like a high pressure problem (unless this hasn't been run in years, in which case a full current burn for a couple hours should fix)
 
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indeed. unlike hene lasers, just because a psu hooks up to a argon tube and meets its specs, doesn't always mean that the tube will like it.
 




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