CurtPalme.com Home Theater Forum

[stefuel]

A few months back Athanasios sent me a used Thomas tube (Thanks Athan) to experiment with. I was curious how hard it would be to mod AmPro neck boards to work with them. This was (according to Athan) a 6K hour tube. At 6K hours it still looked to be a 8.5-9 on the phosphor scale and that was a green. I spent a afternoon modding a neck board to work with it and it fired up perfectly. Any way, jump ahead a couple of months, the last green LCP I had to my name went belly up.
Then I remembered I had that Thomas tube and modded neck board. Well lets just glue that sucker up in a AmPro housing and see what it'll do. IT DO GOOD!!! So good that I ordered a full set of NIB ones from him. They showed up on Wed afternoon and by 8:00 PM the first one was glued into a LC coupling. I swaped in the second of three tonight but will have to wait till Sat. to do the third as I have to work tomorrow night. After that, I still have two more neck boards to mod.
When the boards are complete, I'll test them on the used green before I put them on new tubes. That's it for now. I'm falling asleep at the keyboard.

[Nashou66]

Glad they made it ok Chip!! Your Check also Arrived ok that will be deposited tomorrow.

I cant wait to hear how these work in an ampro !

Athanasios

[cmjohnson]

I'm not surprised to hear that Thomas tubes are good. The company makes a lot of high performance CRTs for specialized applications,
and in the past made more conventional designs, too, though the market is understandably different these days.

Some of you may remember that several years ago I asked Thomas Electronics about the possibility of producing P19 and 180 series
tubes for our projectors. They did say they could do it, but when they actually delivered pricing data, it wasn't anywhere near the
cost savings that I was told I could expect, as per the engineer I talked to. Needless to say, that didn't go very far.

CJ

[stefuel]

All right. Back to work. I'll be spending the next three hours mounting up the last of three new tubes. After that I'll mod another neck board for the blue and time permitting the red. I have a extra green c-element and all the magnetics so I can have two complete assemblies to slide in but no extra red c-elements. I'll save the red for last cause I'll have to rob the red c-element from it.

[stefuel]

OK it's time to install the first of three tubes. I have to do it in stages because I want to test each neck board as I go. I know the original modded board works so I'll install the blue first. Move the proven neck board from the used green to the new blue and test the latest modded board on the used green while it's still in the PJ. If that works OK, I'll slide in the new green tomorrow night, pull the red and slide the used green in it's place to test the modded red neck board. The red board is a different different design so that the tube can swing all the way in. I neatened up the wiring inside and the connectors won't reach unless I cut a bunch of tie raps. If the modded red board works OK, I'll rob the red c-element from the LCP and install it on the Thomas red and slide it in. I'll have the PJ up and running tonight and hope to have the other two tubes installed tomorrow night. I'll rough it in and let it run for a week then do a ground up and calibration next Sunday.

[Nashou66]

Yes, let the tubes break in a bit on a low IRE full pattern with the all the colors defocused to spread the break in over the entire phosphor not just were your drawing the exact lines. Can not wait to hear the results.

Athanasios

[stefuel]

The blue is up and running and looking sweet. The small amount of streaking I reported last week seems to be related to the first neck board I modded as the streaking moved to the blue and the green now looks fine. I'll mod another board for the green now. I'm going to have to see if Curt has some extra sets kicking around. I'm running out. I gave a whole set away thinking I wouldn't need them.

[Nashou66]

Ok its been a few hours any updates?

Nashou

[stefuel]

[Nashou66]

Thats good that the two like tubes will converge much easier than mixing, good thing to know.

Enjoy your social event tomorrow and get that mess cleaned up for the little lady.


Athanasios

[stefuel]

As far as "spot size" goes, I may have to eat my own words. Upon closer inspection, the spots look to be the same size but there is less light scatter. I'm not sure how to explain it. I'm not sure if the gun can focus better or the phosphor is holding the light tighter but it is a much sharper spot.

[Nashou66]

[cmjohnson]

I've read several references to Thomas tubes lately. What's up with that? Where are they coming from? .gov surplus or something?


CJ

[Nashou66]

Nope, I bought the remaining stock of new tubes, and a bunch of used ones.

http://www.curtpalme.com/forum/files/got_tubes__175.jpg




Athanasios

[cmjohnson]

Your projector is not perfectly level to your screen.

My noting that setup error is a service I have just provided to you. It will cost you one set of those tubes.

So, what, did you buy them directly from Thomas?


CJ

[Nashou66]

[LOTREE]

[stefuel]

Tonight I'll install the green c-element, fill with coolant, install the magnetics and shielding. Thursday night I'll mod another board to replace the streaking one and hope for a Friday swap. I have to work on Sat. If I get everything swapped out on Friday, I'll shoot for a calibration on Sunday. This winter is killing me. I have no free time

[cmjohnson]

Wow...soome of those WERE mine at one time!

Man, I've got to say it...when you don't even remember that you had that pile of stuff yourself once, you've been pretty busy!


I honestly don't remember much about them. Practically nothing, as a matter of fact. Except I do recall rewiring an old 8000's neck
board to run with them and actually ran one briefly without an LC assembly on it. I was just very careful to ground the dag to the
chassis. It looked good but it was hardly a precision test.

I'd really forgotten all about them.


CJ

[Nashou66]