URGENT-Get Your CRT Tubes Rebuilt Soon!

[John Marinello]

Originally Posted by AUdubon5425

I'm going to call him about my 23MP4 when my tax refund arrives.

Has anyone written up directions for the proper way to pack a CRT for shipping?

Video Display has 8 23MP4 CRTs, $139 per each, you could buy a spare for
what Scotty charges:

http://vdc.mybisi.com/product/56478/23MP4_416108.html

[Eric H]

Originally Posted by John Marinello

Video Display has 8 23MP4 CRTs, $139 per each, you could buy a spare for
what Scotty charges:

http://vdc.mybisi.com/product/56478/23MP4_416108.html

Do not depend on their Site to give you accurate information on what's in stock.

They did not have any 12WP4'S in stock despite the Site saying they had 9.

[jhalphen]

Hi to All,

On the topic of CRT rebuilding, over here in Europe we are not sitting on our butts doing nothing!

Witness, for instance this rebuild by French Co. RACS of a very rare pre-war Telefunken tube model RFB/VI-1 for our friend Eckhard in Germany.

RACS gave me permission to post these pictures, so here they are.

Rebuild was routine, except for the electron gun which the Lab commented "Had the complexity of a "Rube Goldberg" device": successive interconnections of focussing grids in the sequence G1-G2-G1-G2-G1-G2

The gun was entirely rebuilt, using the original metal electrodes which were remounted in a "copycat" entirely new gun.

Other interesting comments: the supplied tube was down to air, so of course it was cleaned out to all transparent glass then new P4 phosphor was applied. RACS commented that the internal side of the faceplate was slightly damaged by the many years the CRT had been down to air, so minute internal surface irregularities can be seen (with your nose on the screen!) after recoating.

And, oh yes, the CRT glass is Pyrex and rebuilding involved the now mastered art of fusing "salami-slices" of different glass softness to match Pyrex to soft glass.

Each picture is named with the proper step description in the rebuilding sequence.

Next step in the project is "bring your dead CRT to the ETF Convention" May 1-2-3 for a bulk shipment of 10-15 tubes to France to save on shipping costs.

Best Regards

jhalphen
Paris/France

[jhalphen]

Telefunken pre-war CRT, 2 last pictures

[John Marinello]

Originally Posted by Dan Starnes

I need to get my Predicta Holiday CRT to him, good idea on the tax return, that is what I will do with mine.
Dan

What CRT does the Holliday use? 17 incher?? If so, I may know someone who has an NOS one.

[John Marinello]

Originally Posted by jhalphen

Hi to All,

On the topic of CRT rebuilding, over here in Europe we are not sitting on our butts doing nothing!

Witness, for instance this rebuild by French Co. RACS of a very rare pre-war Telefunken tube model RFB/VI-1 for our friend Eckhard in Germany.

RACS gave me permission to post these pictures, so here they are.

Rebuild was routine, except for the electron gun which the Lab commented "Had the complexity of a "Rube Goldberg" device": successive interconnections of focussing grids in the sequence G1-G2-G1-G2-G1-G2

The gun was entirely rebuilt, using the original metal electrodes which were remounted in a "copycat" entirely new gun.

Other interesting comments: the supplied tube was down to air, so of course it was cleaned out to all transparent glass then new P4 phosphor was applied. RACS commented that the internal side of the faceplate was slightly damaged by the many years the CRT had been down to air, so minute internal surface irregularities can be seen (with your nose on the screen!) after recoating.

And, oh yes, the CRT glass is Pyrex and rebuilding involved the now mastered art of fusing "salami-slices" of different glass softness to match Pyrex to soft glass.

Each picture is named with the proper step description in the rebuilding sequence.

Next step in the project is "bring your dead CRT to the ETF Convention" May 1-2-3 for a bulk shipment of 10-15 tubes to France to save on shipping costs.

Best Regards

jhalphen
Paris/France

Looks like there's a metal tube in the background, are they having good luck rebuilding those?

Also, can they aluminize tubes, and would a super-bright picture be somehow undesireable on a prewar set?

If they can aluminize tubes, how about metal CRTs? I heard that it was a difficult process due to the tight corner formed at the faceplate/cone bond. The specs on the 19AP4C states aluminized, but I've never seen one.

[vintagecollect]

I may have a CRT to send to you to france, it's gone to air , DO the rebuild CRT projector tubes jphalen? I need a single red phospor CRT projector tube rebuilt that has gone to air with an open filament??

please reply

[jhalphen]

Hi to All,

For John Marinello:
Q: Looks like there's a metal tube in the background, are they having good luck rebuilding those?

A: Will ask today

Q: Also, can they aluminize tubes, and would a super-bright picture be somehow undesireable on a prewar set?

A: Yes they can, in fact it's part of the normal routine. However, for TVs which have an EHT of less than 8kV, the screen is not aluminized. Reason? under 8kV, electrons don't have enough acceleration to get through the aluminum barrier, hence no picture or very dim picture. The 8kV limit was determined by experimentation + experience (RACS has been in operation for 35 years +)

Q: If they can aluminize tubes, how about metal CRTs? I heard that it was a difficult process due to the tight corner formed at the faceplate/cone bond. The specs on the 19AP4C states aluminized, but I've never seen one.

A: Will ask today, i'm fairly confident they can, over time they've dealt with a considerably variety of tubes, B&W and Color, consumer & military.

For Vintagecollect:

Q: I may have a CRT to send to you to france, it's gone to air , Do they rebuild CRT projector tubes jhalphen? I need a single red phosphor CRT projector tube rebuilt that has gone to air with an open filament??

A: will ask today. Tube ident, manufacturer & basic data would help.

please reply - Will do! as soon as i get answers.

2 things you all should know:
- I don't work RACS, nor have any business ties. Like all people on this forum i'm into vintage TVs, and when i learned that we still had a CRT rebuilding facility in France, it seemed an interesting challenge to nurture contacts between this Co. and the worldwide community. In other words, i help with all the language, translation & cultural aspects.

- RACS rebuilds tricolor CRTs, but like all companies in this trade, they cannot re-screen a tricolor tube. in other words, guns YES, screens NO.

Best Regards

jhalphen
Paris/France

[jeyurkon]

Hi jhalphen,

Additional questions: When they re-phosphor a P4 CRT do they use the original silver activated Zinc Sulphide + Zinc Cadmium Sulphide or do they use the modern cadmium free P4 replacement?

The modern replacement doesn't look as nice to me because the three components are randomly distributed when mixed. Since it's random it can't be perfectly uniform. You end up with colored blotches. I seem to be the only one that complains about this. Even a color CRT with a monochrome picture looks better to me because it is uniform. Oddly enough I have defective color vision but am still sensitive to this.

Actually, on a large CRT I'd be sitting back far enough to not notice it, but on a small 8" or even 12" it really shows up.

I understand the need to go to cadmium free phosphors, but if they're allowed to use the original for vintage or historical restorations, that would be great.

John

[jhalphen]

Good Evening Gentlemen,

Answers from RACS, today, late afternoon, France:

John Marinello has a sharp eye indeed to see a glass-metal tube behind the Telefunken! - see pix below.

Metal/glass tubes are no different for us than all-glass tubes. Of course, there can be problems of separation and cracks at the glass/metal boundary, these are known problems and we have means to solve them, not always, but frequently.

Successful rebuilding of glass/metal tubes:
Success depends on mastering stresses at the glass/metal boundary, we have good experience in this domain, but no one can guarantee a 100% success rate in this operation, old glass/metal has it whims and CRT rebuilding is a mix of science & know-how, therefore some fail.

Tube aluminizing:
Correction: OK for tubes at or above 12 kV EHT, not 8kV as quoted earlier. My mistake or new directive, i don't know.

Aluminizing metal envelope tube:
Aluminum is evaporated under vacuum inside the CRT. The vaporized aluminum is therefore deposited everywhere, but in this precise case, the aluminum deposit is only important on the screen, not on the bell, which being made of metal, already has excellent conductivity. If some aluminum is not deposited on the bell and there are bare spots, the EHT wiil circulate without problems and it is not a small bare spot which will impede its passage.

What is really important, is the quality of the Al deposit on the phosphor layer. if you look at the photograph, you will see that the evaporation filament is in the direct axis pointing at the screen. Nothing will prevent the Aluminum from being deposited wether the screen is all glass or glass/metal.

For Vintagecollect:
Awaiting your data on the Red projector CRT.

Best Regards

jhalphen
Paris/France

[jhalphen]

Good Evening Jeyurkon,

Questions duly Noted.

Will transfer tomorrow & hopefully expect fast reply.

Best Regards

JH/Paris

[jeyurkon]

Thanks for the photo of the CRT being aluminized. That's cool!

Is the orientation of the photo the same as how the CRT was oriented? That is, was it horizontal?

Most evaporation sources that use a boat would require the screen to be at the top, otherwise the aluminum would fall out of the boat. If they use a stranded tungsten coil that is wetted with aluminum, then I could imagine it being in the orientation shown.

John

[eberts]

How current are those photos ?
I saw a reprocessing plant in 1963 that used the same rescreening equipment in the USA.
The next year it was all scrapped and closed, color TV gained acceptance, killed the profits and the B&W customer base.
I remember B&W rescreened tubes could be purchased for $4.95 to $9.95.
The electron guns could be bought for 35cents each in quantity.

[jhalphen]

Hi to All,

Reply for Eberts:

> How current are those photos ?
Very recent, the telefunken tube was done a few weeks ago

> I saw a reprocessing plant in 1963 that used the same rescreening
> equipment in the USA.

Rebuilding tubes is a mixture of technology, know-how, and art. This was refined in the 50s and basically hasn't changed. A tube work station looks the same everywhere.

Now RACS is not a Mom & Pop operation using a DIY 1000$ kit like were widely sold in the US in the 60S. RACS is a small industrial outfit, been in business for 35 years, and have heavily stocked up on CRT components, glass, chemicals, etc. to continue offering the service for at least 5 years. BTW, they do a lot of MIL work for radar & head-up display CRTs.

Have a look at their site:

http://www.tube-cathodique.com

> The next year it was all scrapped and closed, color TV gained acceptance, > killed the profits and the B&W customer base.

RACS rebuilds B&W, monochrome (green, yellow,..computer screens) AND full color CRTs.

> I remember B&W rescreened tubes could be purchased for $4.95 to $9.95.
> The electron guns could be bought for 35 cents each in quantity.

Yes, well, those were the prices 50 years ago!

We are not trying to compete head-on with US rebuilders, but rather to offer an alternative when the US plants close down, in 2 years max, or less.
There is also a collector market in Europe, mainly the UK & Germany so far.

Best Regards

jhalphen
Paris/France

[jeyurkon]

Thanks, that link answered my aluminization question.

John