CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Here are the first tubes I've taken to test out of a lot of (so far) 47 P19LUG tubes I've acquired from...somebody.

I hand picked all the best looking tubes out of the whole lot of some 250-odds tubes that my source had.

They're all simulator pulls, changed on hours of usage. Which, depending on the simulator type, is either on a 2000
hour changeout schedule or on a relaxed "Run them until someone complains" schedule.

SOME tubes may be absolutely new, potted up into an LC chamber, and then removed before it was even installed
as the program it was intended for discontinued CRT refurbishment in favor of switching to digital projectors now that
they're FINALLY getting to the point that they're night vision compatible.

It's possible that some were rejected for minor flaws.

These were just the first three I picked and cleaned up and prepared for potting. After sticking an anode lead and
magnetics on them, and ground straps, it was time for a BRIEF test at low contrast, since with no cooling system
attached they would burn very quickly if run at normal contrast levels.

The red looks absolutely perfect. No visible wear or defects of any kind. Of course it's going to get potted up in short order.

The blue appears to have been rejected for a phosphor flaw you can see. One tiny little black spot in the upper right middle area. This is very sensitive and fresh, G2 and drive levels needed for a good grey scale are very low as is typical of a new tube, and I believe that it is in fact absolutely a new tube still in its first hour of usage.
Would YOU be happy to find this tube in your projector? Or would you complain?

The green is also a very fresh-acting tube. Super low G2 and drive levels. But it does have some very slight pattern
wear. It's visible, but most of it would be outside a 16:9 raster area. I'm going to hold off on potting this one
until I've reviewed my other 8 greens. I suspect I have better ones.

My goal: Two perfect sets of tubes to convert my two 8500s to 9500LCs. The red one is good enough.

Is the blue?

Would you find the green acceptable for (A) movies and TV, (B), gaming, or (C) get that trash out of my projector! ???

The first pic is a photo taken of several CRTs illuminated by a black light. It activates the phosphors and allows me to
see wear that is not visible in white light.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

You can see that I'm trying to be pretty critical. You don't even see the wear pattern on the green unless you look at it for a few seconds. At least that's my impression.

I want your second opinion. And your third, fourth, fifth, etc...

Ultimately I want to have four refurbished Ultras that will eventually be sold, and I want them all to have tubes in them that
the buyer will be very happy with. So it's not MY opinion that really matters, it's YOURS.

Oh..the broad line in the blue tube is an artifact of the photograph. A longer exposure would have eliminated it. No such bar actually exists on the CRT face.

The yellow hot spots in the red are also camera artifacts. I have no concerns about the red. It IS perfect, and I can see absolutely no wear on it at all.

Since these tubes came from flight simulators, I expect more wear on blues than any other tube.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4378 Location: Phoenix

Hey

Red looks pretty good, green has a little wear. Someone can likely enjoy the green at the right price. Unfortunate that there is a dark spot on the blue, but possibly usable for someone.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm thinking the blue is "gamer grade" and will be sold separately, not put into a projector. But a NICE "gamer grade" tube.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4378 Location: Phoenix

Hey

Green and blue might not command $800 but they might bring $400/$500........?

I have been running a green tube with some ordinary wear for years, and I do not notice it unless something comes up all white or all green.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

The spots on the blue tube are not visible with the tube turned off. It may be a condition that can be covered under VDC's warranty. I have made inquiries. Hoping for a positive answer.

What's really weird is that the "dead spot" glows just like the rest of the CRT phosphor when illuminated with the blacklight.

This indicates that the phosphor is being blocked by a contaminant inside the tube which is adhered to the back of the phosphor coating.

There is a slight chance that the blocking contaminant can be knocked off by gently tapping on the tube with a rubber mallet.
But before attempting that, I'll find out about warranty status. I don't want to risk breaking a tube that I can exchange.

the big E · Joined: 20 Apr 2013 Posts: 1928 Location: speedwell Tn.

My dwin has a blue tube with a wear pattern that looks worse then that green tube

I wouldn't complain about it as I have seen worse (try near or toasty tubes)

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I've seen tubes that were so toasty that when you looked at the CRT face (tube turned off) you literally were looking at a tube face that looked like a piece of toast! Burned toast. Brown to black all over. And pretty much no emission left.

The hours meter said something absurd, like 60,000 hours and I believe the tubes actually had that many hours on them. They don't get that brown without a LOT of hours on them.

I never understood how they could even get that bad. Why keep running the picture when the image is so bad you literally can't even tell what you're looking at? Shut it off and stick it in the storage room.

barclay66 · Posted: Wed Apr 27, 2016 7:13 am Post subject:

Hi,

From my point of view, the red one is the only one that I would put into a PJ for sale. The blind spots on the blue makes it completely unusable (except for testing purposes where spot burn may occur). The green is somewhat tricky as it incorporates a psychological element. The viewer not knowing about the light usage pattern may not notice it at all during its remaining lifetime. The one knowing about or noticing it (depending on setup, content etc.) could feel increasingly annoyed. Even in situations where the actual edge between used and unused phosphor is invisible. At least that happened to me at the time I had to use a green which had a very light pattern. Once i had noticed it on a very bright scene, I got stuck into "scrutiny mode" looking for it whenever I watched a movie...

Regards,
barclay66

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

I agree on the blue with Barclay, I had spotburned tubes some time ago, and even if I can't make it out directly looking at the raster they were well noticeable on screen. Now I see not one but four spots on the blue, these are easily noticeable even on the bare tube, so they will be huge projected on screen.
Also the green pattern is way too narrow, it will be instantly noticeable in 16:9.
Great tubes for charity purposes Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Good, good! Keep those opinions coming!

Sorry, I can't afford charity work. Besides, there may be hope for that blue yet. If I can get a warranty replacement, that's awesome. If I can't, the contaminant might be dislodged with some very carefully considered taps with a rubber mallet.

Personally I know I could live with that blue dead spot if I didn't already have two perfect sets of tubes for my personal projector. But I'd want a discount for it!

**kal**

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm just trying to get some sort of consensus and range of opinions. I will have many working tubes but not all of them will be perfect, obviously, and some of them may not be worth potting into LC hardware. Of course the very best will be potted up before any second or third rate tubes, but it may come to the point where I have to choose between imperfect tubes to pot up and
knowing which ones are more desirable in the general consensus will help me to choose the right ones.

Or I may simply choose NOT to pot up any tubes that are imperfect, but show them running, and if someone needs a B or C grade tube (priced accordingly) then he can choose the exact tube he wants, within that category.

I wish that I didn't even have to make these choices and could just pull fresh brand new tubes out of the box and know that they'll always be perfect, but that isn't my situation. So choices must be made.

It appears that if I can solve the C element stock problem, I'll end up with more LC hardware than tubes to pot into them. In that
case, every decent tube will get potted and prepped for sale/ exchange. The plan is that I will be able to offer assembly exchanges. Buy a tube from me, it arrives in a complete LC assembly, ship the existing LC assembly back to me, I recycle the bad tube, and I put the hardware back into play. If there are more tubes to use.

More likely, the remaining CRT retubing market continues to shrink and I may sit on spares for a long time and I may never
even be able to sell some. But that's OK. I'd rather try than not try.

**kal** · Posted: Wed Apr 27, 2016 2:10 pm Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

And, in this batch of retired simulator tubes, if there is a wear pattern it's not going to be 4:3, full raster, and even. Unfortunately, but that IS why I spent a lot of time evaluating the tubes and picking only the best of them.

**kal** · Posted: Wed Apr 27, 2016 2:21 pm Post subject:

Uneven wear wouldn't be something I'd like.

The thing you need to take into perspective is that the chassis / setup that these would be used in are high end 9" machines. Most people willing to sink money into something like that are only going to want something perfect. That means no uneven wear, no phosphor defects/burns. What's the point of having a high end CRT projector like a Marquee 95xx if you're going to cripple it with visible uneven wear or spots on the screen? To me, that's like owning the best stereo in the world but only being able to play AM radio on it. Wink

Again only my opinion, but something like uneven wear or spot burns/defects are things that that only bargain CRT owners (7"/8") are going to accept and only if it's a cheap machine (a few hundred dollars or less). A junk machine to tinker with or to let the kids watch stuff on, or game on. Wink

Kal

the big E · Joined: 20 Apr 2013 Posts: 1928 Location: speedwell Tn.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

See this? One of the .gov surplus Marquees I bought, years ago, had three tubes that made the one seen here on the left
look like a new tube in comparison. That was the one with 60K hours on it and no emission to speak of.

just to read the hours meter I had to turn all the lights off and swap the green signal cable to the best of the three tubes and I STILL had to wait for my eyes to adapt to the dark before I could read it!

I had photos of it, once. Probably long gone or in my old retired PC.

the big E · Joined: 20 Apr 2013 Posts: 1928 Location: speedwell Tn.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I've hung anode leads on seven more tubes that go to test after the silicone has cured. Tomorrow evening. I went ahead and put leads on three of the greens this time around because, well, they're of highest importance. They all look better than the first tested green, even to the naked eye, so I expect good results out of them.

Actually, the first green I tested (pictured in the start of this topic) appears to be the WORST green I have based on visual inspection of the greens. I find that to be encouraging.

Also, one of my 9500LC Ultras that I picked up has two greens in it, which is great, because it's a minty tube and just helps out my inventory that much more.