True, the 15GP22 uses electrostatic convergence; however, regardless of the method of convergence in any color tube, the outcome is the same - focusing the electron gun on the phosphor plate. Of course, the physical principles and subsequence circuitry is different (15G uses electrostatic fields and the 21AX gun uses magnetic). Say, glad use did mention the use of 21AXP22 guns - it would be cool to find out who tried it and what finally came of it.

On the subject of phosphors, I've had the unpleasant experience of discovering the non-aluminized black & white tube phosphor the easiest to damage if you suddenly break the seal off nipple at the base of the gun. You can blow away a circular patch of phosphor several inches in diameter off the face plate. I recall calculating the velocity of air once as it enters the tube. At the instance the nipple is broken air rushes into the tube at something like up to 300 miles per hour - depending the length of the tube. Air traveling at this speed does a nice job of blowing away the phosphor. Sort of like sand blasting the phosphor off the glass! Of course, aluminized phosphor is strong enough that this doesn't seem to happen. Guess if you're going to go to all that trouble to rebuild a 12AP4 pre-war tube to recoat the phosphor you're basically building a whole new tube. At least it looks authentic on the outside - not sure how safe the integrity of the old glass bottle would be though. Why not take the last step and replace the old glass too!

If there was a way to replace the glass at a reasonable cost, making a whole new tube would be an attractive alternative. However, the cost of building the molds and having the shells produced would be prohibitive, especially with the limited number that are needed.

---

How about the Sylvania "new gun and screen" tubes...did they maybe cut off the front part of the tube?

Aren't almost all color tubes made with two piece shells?

I believe if you look closely you'll see a bonding agent holding the front of the tube to the bell, how else could they build them?

15gp22
 

Since Eric opened a can of worms on the 15gp22..LOL..I have a dud 15gp22 in the basement,i also sold my ct-100 last year to a guy in france.(working).
so i called this place that says they can rebuild the 15gp22 and others.
A lady who answered the phone took my name and number down and are suppose to call back,i will let you all know what is what.!:)
terry

---

15gp22
 

well its been several hrs since i called them.
no return call..so i called them a 2nd time,this time a guy answered and didnt speak very good english at all,as a matter a fact i had to ask him to repeat what he said..finally he said.. "someone will call you back about 5:00-5:30 pm". click
maybe they dreamed they could rebuild the 15GP22?
kinda like i dreamt last night my Male cat had kittens..:)
terry

Questions for the 15GP22 Rebuilder
 

If you get a hold of someone (guess you've already figured out not to hold your breath...) and you get a price I think it might be a good idea to find out just what these guys are doing. Why not ask or email them for details. After all, you got a rare tube. Here're a few questions I would ask:

1) Physical damage to the tube face plate - if so then it may not be repairable. Any scratches or chips may cause tube to implode of crack during baking. Then again, it may not. Just all depends on the damage and where. For a sizeable chip of glass out of a corner of the tube may be courting disaster!

2) Is the tube at air/low vacuum/condition of the getter (silver or white)?
If tube is still under vacuum and getter is silvered then:
What is their inspection process?
If tube is at air do they break the seal cut off the old gun assembly?
and then connect the open funnel stub to a vacuum chamber to do a
slow outgas pre-bake at 150 deg C to drive off water vapor?
It's a hell of a lot easier to pull water out of a 2" stub than a 1/4"
evacuation nipple to pressures of at least 10-6 torr!

3) What's their experience rebuilding the 15GP22? References?
4) What's their rebuilding process? In house or RCA?
5) When they break the seal to start the process do they do it vacuum?
6) Once the seal is broken do they back fill the tube with dry N2 gas?
It may be necessary to physically handle the 15GP22 by hand unless
the rebuild chamber can accommodate the tube easily and be kept
under vacuum at all times.
7) How do they alignment of the gun with the phosphor plate?
8) Do they know which gun goes up?
9) Where did they get their replacement gun assembly?
10) Are they capable of rebuilding the electron gun with new filaments?
11) How do they prepare the tube?
12) How do they prepare the replacement gun?
13) What maximum temp do the bake the tube?
There is no need to exceed 300 degC. Maximum tip off temperature used according to RCA research papers described limiting the original manufacturing process to this temp for the 15G. I would suggest not exceeding 200 DegC but, instead, allowing the tube to bake for a day then gradually reduce to room temperature over 7 days.
14) Are they doing anything special to prevent thermal shock to the phosphor plate?
15) Do they thermally cycle the tube? If so, periods and ramp times?
16) Do they do local annealing of the new glass seal on the gun assembly?
17) What is the maximum tip off temperature during baking?
18) Do they helium leak test the face plate to cone (funnel) seal?
A helium leak test of the feed throughs at the gun base after a replacement gun it critical to make sure the replacement seals are good.
19) Are they able to place a 20KV charge to stress test the tube?
The ability to stress test while actively pumping the tube before sealing allows the rebuilder to further outgas the tube. Especially since these tube have been sitting around for 50 years.
20) How long do they evacuate the tube before sealing?

I suspect that attempts to build these tubes in the past have failed not because of the gun replacement parts (...don't rule anything out though!) but because of suspect improper evacuation, outgassing and stress testing before sealing the tube before finally firing the getter. In my mind, there's no reason why a 15GP22 can't be easily rebuilt. However, if the tube rebuilder thinks they can do a regular 'slap and dash' job like on a modern all glass CRT then it ain't going to be so! Success takes time, exceptional vacuum technique and extreme patience, especially with the rebuilder taking their time not baking the tube to the point where seals and/or phosphor plate are damaged.

Anyways, give it shot. Let's see what they say.

Tom

15gp22
 

well its obvious they are not going to return calls as they said..
why would a company mislead about something as this?.i bet they dont really even rebuild the antique tubes they say they can do..maybe it was suppose to say "ANTIQUE TUBES NOT REBUILDABLE" ...but they coulda told me on the phone or called back..maybe ill stick my dud 15GP22 that i have no chassis for into the kitchen oven and see what will happen..:)

I don't think they rebuild any tubes. Notice all the other activities they supposedly are involved in.

15gp22
 

this is a cut and paste of what they say on their website...below
************************************************** *****
Below is a listing of the types of tubes we rebuild at WMicronics.

Rebuilt Color Picture Tubes
A66EAF51X01 A66EAK00X01 A66EAK22X21 A66EAK51X01
A66EAK71X11 A66EAS01X01 A66ECF25X05 A66JMZ30X01
A66EAK071X11 A66EAK252X11 A66EAK552X11 A66EAS00X01
A66EAS13X01 A66ECF00X01 A66ECF10X05 A66ECF25X01
A66ECF50X12 A66ECF61X71 A66ECY13X01 A66EHJ43X01
A66PNT16X A66ACT07X A68AGD01X A68EAU25X02
A68EGD032X322 A68ESF002X11 A68ESF002X111 A68ESF002X43
A68KVL74X01 A68KZN696X99 A68EAU28X01 A68ESF002X143
A68JUA125X A68KKN96X01

Screen diagonal 28" and 29" with Full square or Full and Flat.


Rebuilt Black & White Picture Tubes
3KP4 5BP4 7DP4 15GP22
21AXP22 21CYP22

These antique tubes are rebuildable,and can be rephospored. Gassy tubes can be rebuilt. Contact us for a quote.

[QUOTE=On the subject of phosphors, I've had the unpleasant experience of discovering the non-aluminized black & white tube phosphor the easiest to damage if you suddenly break the seal off nipple at the base of the gun. You can blow away a circular patch of phosphor several inches in diameter off the face plate.>>>

Probably is a way to do it by putting some flexible filter or device over the nipple so when it is broken, the air has to go thru the filter or something like that to slow down the de-vacuuming of the tube (?) Maybe just a little rubber hose slipped over the nipple with a filter or pinhole plugged into the other end of the hose.

Squeege real hard ...then squeeze some more!
 

[QUOTE=frenchy][QUOTE=On the subject of phosphors, I've had the unpleasant experience of discovering the non-aluminized black & white tube phosphor the easiest to damage if you suddenly break the seal off nipple at the base of the gun. You can blow away a circular patch of phosphor several inches in diameter off the face plate.>>>

Probably is a way to do it by putting some flexible filter or device over the nipple so when it is broken, the air has to go thru the filter or something like that to slow down the de-vacuuming of the tube (?) Maybe just a little rubber hose slipped over the nipple with a filter or pinhole plugged into the other end of the hose.[/QUOTE]

Frenchy, the early non-aluminized tubes were coated with phosphor that were typically atomized or gravimetrically settled onto the face plate via a liquid alcohol suspension. Baking the tube during evacuation removed the volitials and leaves the phoshpor on the face plate. The only practical way to bring these tubes up to air without disturbing the phosphor is using a very slow leak. Specialty equipment used during rebuilding usually places the entire tube in a vacuum before the vacuum in the tube is breached (usually the neck is cut off to replace the gun assembly). Using a filter on the nipple I doubt would work as it takes only the smallest amount of air rushing in at about 300 miles per hour to disturb the phosphor.

Remember there's about 1,400 lbs/ square inch pushing down on a CRT from the outside world. Ya gotta grab onto ur hose and squeeze it real tight to slow'r down!

Finally, an e-mail reply
 

[QUOTE=Steve D.]I e-mailed these folks after reading this thread. No reply yet, but the disconnected phone probably tells the story.

I received this e-mail reply this morning:


Steve:
I am on the road this week and I will respond around the middle of next week,when I return.

Regards
Ian B.M.Charles CET
Western Micronics CDN.International
RECYCLE! for a cleaner Environment
http://www.wmicronics.com
A caribe company
110 - 112 East North First Street
Seneca SC 29678
1-864-985-1556


Steve D.

Western Micronics
 

[QUOTE=Steve D.]
Steve, I also got a similar reply today from Ian Charles. He omits mentioning he'll return! Ha...

-------------------------------------------------------------------------

From: Ian Charles [mailto:[email protected]]
Sent: Tuesday, December 06, 2005 8:21 AM
To: Tom Ryan
Subject: Rebuilding Antique Tubes


Tom:
At present I am on the road and I will respond around the middle of next week.



Ian B.M.Charles CET
Western Micronics CDN.International
RECYCLE! for a cleaner Environment
http://www.wmicronics.com
A caribe company
110 - 112 East North First Street
Seneca SC 29678
1-864-985-1556

--------------------------------------------------------------------------

So, anyone know what's the reference to a caribe company mean? I found the following on yahoo, not sure if this is the one:

Company Profile
Updated: 05-JUL-05


Signal Caribe Inc.

Private Subsidiary, Headquarters Location
St. Just Rd., St. Just PR 00978, United States
(787) 761-2620,
Line of Business: Manufacturing: Manufacture of electronic components.

Add me to the list of those that have a spare 15G dud....

this is why rebuilders have to rephosphor mono crt's.
i change out a few of these a week when rebuilding these control heads.

Now THATS burn-in!

If the brightness had been turned any higher it would have been a burn THRU!
: )

15gp22
 

i e-mailed them this time.. here is a cut and paste..and he never called,my caller id on my phone would have told me so.. and now he says they are closed till jan 2006???

Terry:
I do not know where you get yoiur facts from,I did return your calls,in one instance I left a message and in the orther instances I did not leave any messages,you are no the only person we have call on,on a daily basis, and it is not my fault when I call you are not there,we do rebuild the Tubes but we are closed for the holidys and will reopen the second week of January 2006,we however will be replying to emails every couple of days.
What do you want to find out ?



Regards
Brian Holder
Technical Manager

Damn, we're just a tad touchy, aren't we? What this putzella don't realise is that if he MAKES NICE, there could be a whole bunch of business being sent his way...I'd hazard a guess a reasonable amount of the old-TV fraternity are either members here, or lurkers, & being kinda smart-alecky like that is NOT a good thing...Just my .02 worth..-Sandy G.

Wow... that's some nice English and spelling.

:no:

Don't know if I'd trust very much to this "Technical Manager".

So wiseguy, what exactly did you do to this dude? I wouldn't want to take anything out of context, we all might get the wrong impression; but the references to the number of messages is curious. How many did you leave him? He seems a bit upset about facts. Darn right edgy. The way he tells it, it sounds like you're calling "on a daily basis"? I'd let the litmus test for ESL pass on this guy. Technical managers are not always the best public relations managers - of course some are great at it. Besides, telephone tag has its moments! Say, maybe you could suggest some mutually aggreable time to chat.

BTW, both Steve D. and myself got emails originally from Ian Charles. I plan to give Mr. Charles until the end of this week before pursuing a reply from him. Now, that should be interesting... :scratch2:

Reminds me of an ex-boss I had... He owned the (nameless out of mercy) TV repair shop in (small equestrian section of Northwest Los Angeles County that ends in ___orth)... He once was so upset that I diagnosed a cracked CRT in a Mitsubishi Bigscreen that he ordered me to "SUCK THE AIR OUT AND SILICONE IT BACK TOGETHER" so he could get the repair :screwy: :screwy: :screwy: :screwy:

I wonder if they know eachother?

Charles

I called them 3 x and not everyday,i didnt say anything as i didnt get to speak to anyone,i then left an e-mail asking if the 15GP22 can really be rebuilt and how much and also asked how long..other people have been calling them and e-mailing ..
they emailed me yesterday back.. here is a cut and paste..


Hello.
The tube can be rebuilt,at present I cannot give you a price not until next year as we have just changed Gun Suppliers and will not know the price for a while,until the negotiation with the new supplier is completed ,We will contact you then.



Regards
Brian Holder
1-864-985-1556
1-864-882-6593 Fax



Regards
Brian Holder
Technical Manager

A new gun supplier for the 15GP22? Do they have a time machine?

I'll say what others are probably thinking: these guys don't know anything about a 15GP22 & maybe don't even know if its bw or color. They just assume all old picture tubes are readily rebuildable & why should this one be any different? If they had ever done one before I really think someone on this forum would know about it. If they have never done one before I wouldn't think their luck would be any better than Hawkeye. I would like to find out I'm wrong about all this.

Yeah, I'm beginning to smell a mouse...-Sandy G.

Curious... just how easy is it to find an NOS gun for the 15g? Is it easier to find a gun than the actual tube? Or is it just as difficult? Anyone know of how many guns are accountable now? I'm sure there are some out there, but, it can't be too many. And I'm sure if someone has a gun, it's probably worth more than it's weight in gold!

Oh those optimistic CRT rebuilders!
 

I visited a CRT rebuilder called Superior Tube in Carteret, NJ about 10 or 12 years ago when I was first trying to get my 12AP4 rebuilt. I knew nothing at the time of the obstacles to having this done. But the guy there was in the business, and more than willing to take on the job, so off I went, with all the various pieces of my tube in hand.

However it seems that the "old guy" whom I never met had recently sold the business to his assistant (or was it his accountant?) and the "new guy" was either naively optimistic or perhaps just desperately trying to make ends meet.

What a strange place it was! I should have gone back and taken some pictures. The "inventory" of dud color tubes was kept mostly outside, face down on the front lawn. I guess that probably worked ok, but it reminded me of some kind of weird Halloween display.

Inside, it was dark and dirty. I remember thinking "how can they work on something as precise as the inside of a picture tube with all of this dirt around?". There were racks and racks full of duds inside, mostly color but also one whole section containing "antique" tubes. He assured me that he should be able to find a 12AP4 in inventory, but of course that wasn't to be. But he urged me to leave my tube with him, in fact he would begin the job NOW. He wanted to cut the neck off right away, that day (maybe to lock me in as a customer?) and then order a new gun assembly. Then a few days and a hundred and fifty bucks later, I'd be on my way with a good-as-new tube!

I looked at the wobbly, ancient lathe he was using to weld the new gun assemblies onto the tubes, and the sooty bunsen burner flame that was used to melt the glass. And the steel mesh safety cages surrounding the evacuation area, all of which were full of broken glass on the floor, several inches deep! And I started to think that maybe this wasn't such a good idea!

I didn't know at the time that there was no way he was going to be able to rebuild my tube (and obviously he didn't either), but I got the heebie-jeebies from the Frankenstein-esque atmosphere of the place. I've never been to any other picture tube rebuilding enterprise, but I really hope that's not how it's actually done! I've also been told that someone was selling some kit or franchise (or snake oil?) decades ago which would allow you to rebuild tubes in your garage. I don't know if that could have been true -- does anybody have any info on that?

So anyway I decided to wait a bit before I committed. I'm glad I did, 'cause when I went back a few months later, the shop was gone.

--Dave

Guns for 15GP22s are impossible to find. Guns for the 21 inch round tubes are still around, but hard to find. Anyone who rebuilds a 15G has to rebuild the existing gun.

Speaking of that.......
 

If one did find some old, NOS gun assemblies for 15g's or other old tubes, and they had been sitting exposed to air, for all of this time, they would NOT be useable, would they?? After all, I figure that one thing that makes one tube last longer and perform better than the others, is the purity of the cathode material . So, if an old, unused cathode assembly was welded onto a tube, it wouldn't work very well, would it? or am I totally wrong about this?

an actual 15GP22 NOS-type gun...
 

Here's a link to a graphic on my site of an actual 15GP22 gun that was used years ago in an attempt to rebuild the 15G. We now have new stems as you know, but back then they were not available and so this was someones way of trying to make do. This gun is welded onto a 14AH button, the base for the 21AXP22. No one knows if this approach was ever actually tried, but it seems unlikely. As you can see, this particular guy has been in the air for many years now.

http://home.att.net/~pldexnis/15GP22...em8bitgrey.jpg

What's all the hub-bub? Just go down to Dunbar like I did, and get your 15GP22 rebuilt for $29.50! See the photo?............................................ .................................................. .................................................. .................................................. .................................................. ............ :bs: April Fool in December!

Actually, this Polaroid photo was of the job that Dunbar did for Gary and me on re-evacuating. I mentioned this earlier in the thread, I think (or in another). The result was that the vacuum stayed for about a month, then the neck started getting the dreaded purple glow. Circa 1982.


Charles

Oh, and BTW: The photo is free to be saved & posted elsewhere by anyone....

---

Kaye Halbert, I Pmed You A 2 Personal & Reg. Email But No Response...did You Lose My Address ? G.b. Can You Still Get Picture Tubes Rebuilt In S. Calif. ?

Hey Charles, that's a cool pic. Makes me very nervous just looking at it. Not exactly clean room conditions. About that purple glow, did Dunbar apply VacSeal to all joints - including the evac nipple on the stem? A real shame that the tube lost it's vacuum. Say, I'd be interested in knowing how they pumped the tube - if you can remember the details.

They had two in the midwest in Oklahoma city in the 80's now I think they are gone.

The rebuild saga continues.....
 

I received ths e-mail reply today re:15GP22 rebuild:


Steve:
I will have to get back to you early in 2006,we have just changed Electron Gun supplier and at present I negotiating prices etc. with them so please be patient,at present I have twenty of these 15GP22 CRT,s to rebuild,and as soon as negotiating is completed I will let you know.
Regards
Brian holder Technical Director
Western Micronics CDN.International
RECYCLE! for a cleaner Environment
http://www.wmicronics.com
A caribe company
110 - 112 East North First Street
Seneca SC 29678
1-864-985-1556


Very strange stuff indeed.
-Steve D.