New toy! Uniphase 1145P

[LtKernelPanic]

So I managed to score one of these tubes for $100 shipped and have a question for those who know more about them than I do. I'm going to get the proper supply from MI as soon as I can (which likely won't be until I'm in Phoenix at the end of next month) but was wondering if a lower voltage supply could be used just to make sure the tube works.

 

[ultimatekaiser]

It requires 3800V+ to operate. It takes over 12K just to start it. And even then it's relatively slow to light. Though my tube may be a bit tired. Mine has a short in the anode I think though so I'm tinkering, I may have to bare tube it, which is virtually impossible... It might be partly to blame. Power supplies for this beast are expensive, usually 300-500 bucks...

 

[Sigurthr]

I may have to bare tube it, which is virtually impossible...

Before you do anything mechanically drastic, I've de-headed (beheaded? lol) lots and lots of HeNe's if you need any tips. I've yet to damage a single tube.

 

[ultimatekaiser]

Before you do anything mechanically drastic, I've de-headed (beheaded? lol) lots and lots of HeNe's if you need any tips. I've yet to damage a single tube.

Same. The real issue is the length and the fact that the ballast potting is not the same. Instead of a silicone potting in the tail cap, they have a very hard cement-like potting in the rear of the tube around the anode mirror mount. You can't just heat it and slide it out. I will likely have to cut it out.

 

[Sigurthr]

..., they have a very hard cement-like potting in the rear of the tube around the anode mirror mount...

Wait, they epoxied ON the mirror mount (absurd!)? Or do you mean the end cap has the epoxy, but the alum tube is only RTV Siliconed (not uncommon)? Or do you mean they epoxied on the alum tube but not touching the mirror mount, but it would be in the way of the tube if you were to try and extract it (very strange)? I usually scrap the OEM/original ballast and use a new one (of equivalent value) anyway, I haven't found it worth it to try and dig out the ballast resistor from the hard-ish potting.

 

[ultimatekaiser]

I will take pics. It's hard to explain. Basically they put the tube in and then put a doughnut shaped thing in the end (the mirror mount goes thru the middle) then a black something over the mirror mount. The ballast is strung around the mirror mount in this hollow doughnut shaped tray, and then the tray is filled with hard sandy green potting. It's quite strange.

 

[Sigurthr]

Sounds like my third option, very strange indeed!

 

[ultimatekaiser]

Yeah it's not the rubbery stuff. It's like green colored sand/cement almost. It'll be tricky to get past.

 

[MarioMaster]

Yeah it's not the rubbery stuff. It's like green colored sand/cement almost. It'll be tricky to get past.

Yup, I de-tubed some HeNes a while ago and ended up destroying the ballast resistors trying to break apart the potting compound.

Also carbon composition resistors are pretty expensive (carbon film resistors are more likely to arc over due to the high voltages present in HeNes) So they can be somewhat costly to replace.

 

[LtKernelPanic]

It requires 3800V+ to operate. It takes over 15K just to start it. And even then it's relatively slow to light. Though my tube may be a bit tired. Mine has a short in the anode I think though so I'm tinkering, I may have to bare tube it, which is virtually impossible... It might be partly to blame. Power supplies for this beast are expensive, usually 300-500 bucks...

Bummer. The highest voltage supply I have is 3100VDC from my green HeNe. Guess I'll just have to take their word for it that the tube works until I can get a proper PSU in a few weeks.

 

[ultimatekaiser]

Well....if it weren't a head I know a way. But it's hard on the tube, so I wouldn't worry. Modern tubes are pretty tough in the head. It should still work provided it hasn't been used as a hammer

 

[LtKernelPanic]

Yeah as long as I don't hear glass rattling when the head gets here it should be ok. I may just break out the plastic and order that supply now instead of waiting until I'm in Phoenix next month. After thinking about it I don't think I'd want to carry that PSU on board a plane in either my carry on or checked bag because I can just imagine some TSA clerk seeing that on x-ray and think they found the next OBL which would likely lead to an awkward conversation with the FBI I'd rather not have.

 

[LtKernelPanic]

Tube came yesterday packed in an original shipping box for another 1145P head so no rattling glass. Yeah! As figured my highest voltage PSU didn't fire the tube. Boo! Ended up ordering the right PSU for it from MI since I have a 6 moth no interest thingy from paypal. Can't wait to see this thing fired up.

 

[KapHn8d]

Sweet... thanks for sharing the pics with descriptions. Congrats on the new member of the family

/c

 

[ultimatekaiser]

It's quite the beast for a coaxial tube

 

[Walker16]

I just got 1 too from a coworker who didn't want it