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FrozenGate by Avery

Lasos Start-up problem

Can I be running too much fan for cooling? I don't think so but I believe they need to run a little WARM. I can easily touch the glass area around the hot cathode.

Yes you were running it with a bit too much fan and it has caused your tube to go low pressure, You should be able to touch the glass by the cathode end and it should run very warm, not enough to immediately burn you , but enough to where you won't want to keep your finger on it for more than a second or two. Say 170-190 degrees F

It is reversible if you run it a little warmer with less fan, unfortunately these tubes cannot take the heat treatment torture/ oven treatment you can do to uniphase tubes very easily.
 





Chris -- With the cover off and the fan on the main fins, I could touch the glass cathode area for several seconds. It's starting fast now. Today, first pulse.!!

Thanks -- Mike
 
Update on all of this.

I spoke with Chris today and it appears that I have too much cooling fan. The tube never gets too warm let alone hot with my monster fan. The exhaust air from the fan should feel like a low to medium hair dryer. Mine felt "sorta" warm.

I'm running at ambient air temp of 63 Degrees F and with the fan choked down by 66% now, I read exhaust temp of 100 Deg F at half power and only 85 Deg F at full (45 mW -- 8 Amps) full power. Chris & I think 140Deg F is about right for exhaust air.
This may require more study.

It is possible that I have been over cooling my tube. These need to run WARM.

HMike

10/17---- I'm using a Rotron PT2B3 fan rated at 235 CFM. Running full open, the air coming out is a little above ambient not letting the tube get warmed up. I'm looking around my junk pile for a smaller (quieter :-) fan) I will monitor the temp at half and full power. Understand that ambient temp will play a major factor here where delta T is involved.

More -- I've used a Variac to cut fan voltage to a "quiet" 60 VAC. That cuts the airflow way down. After 15 minutes, the delta T is only +20 Deg F. 105 Deg F exhaust temp. The beam is bright. This is at half power. I will now set it to full power drawing 8 Amps.
 
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Sort of a btt post here.

As I posted above, I'm now running my 235 CFM fan at 60 VAC. The fan is quiet now and The Lasos is running well.

At half power, I read 105 Deg F exhaust temp and using an IR temp meter, I see 120 Deg F on the cooling fins. At Full power, 8 Amps, I got up to 115 Deg Exhaust temp and fin temp of 151 Deg F.
The full power delta T is about +50 Deg F. This doesnt seem too hot for a tube like this.

Are we cooling our ArIons too much?

HMike
 
Mike I'll have to let you know what kind of ΔT I get with my Uniphase argons. They have the stock Dayton blower fans that were OEM to cool the argons.
 
MM --
I tried reducing my Uniphase fan last night too. Its a 2214-30SLQT. WATCH OUT. I have a 212 CFM directly behind the cavity and it needs every bit of fan I can give it.
The Lasos is a different story.

HMike
 
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