Russ Sadler's dohicky

[Doug Fisher]

What is the maximum long life mA rating for your tube model number?

[Gary Richardson]

No idea, it's a cheapo tube with no data about it,

Russ said that for the dimensions of the tube (50 x 1250mm), it'll be a cheap 60 watter, and will run at 22mA,

[Hank Morgan]

Does the tube have any stickers on it with manufacturer and part number?

[Gary Richardson]

Not that i can see, on both the one in the laser and the broken one hung above the workshop.

might be able to find out the details of where it was bought from, but can't usually believe the info they say, as it was bought cheap to get the laser working again after the original tube died,

[Leigh Dodd]

Found this the other day - an E-dohicky

https://www.instructables.com/id/E-dohi ... -Laser-Po/

[Dave Vigness]

Need an actual dimension of the pattern.

I'm using Corel / AutoLaser until I can justify the change over. When I brought the dxf pattern into Corel, it came in at 24" I know Russ said the center line is 'roughly' 12mm, and the program 'should' run for 20.5 seconds. BUT... a larger or smaller pattern would throw that timing off. Am I correct in setting the starting line for 12mm and scaling accordingly?

[Gene Uselman]

Russ' pattern is likely in MM, that might explain the size difference? I would advise buying one from Russ using the instructions earlier in this thread. I have a commercial meter and the exposure time is engraved on the case, it was obviously calibrated against a known standard.

[Martin Berriman]

I got around to using the DoHICky I bought from Russ tonight. Thought I'd post my results in case anyone is interested.
Do these results look sensible? I didn't get a reliable mA reading at the very low settings so I put them as zero in the data.

Martins DoHICky Test Results.png

[Doug Fisher]

FWIW, your curve shape looks generally similar to the one for my 80 watt tube.

[fred ungewitter]

That's an interesting set of curves. A quick search of the 'net suggests that for your tube power, 28 ma is recommended maximum, although at least one user goes no higher than 25 ma. If I read your graph correctly, 25 ma is 65 percent power and provides 80 Watts. That's impressive that your 80 W tube can provide 80W at a safe current draw for maximum longevity. Good for you!