Re-gunned CRM121 tubes - UK Vintage Radio Repair and Restoration Discussion Forum

Panrock · 2nd Nov 2007, 10:02 pm

Just a note to say I spent much of yesterday trying out various CRM121's and a CRM123 which had been re-gunned by Philippe in France - on a Baird Townsman.

I have to observe confidentiality as to who are holding these particular examples but I can vouch for their quality. This should give us a lot of hope for the future.

Steve

tubesrule · 3rd Nov 2007, 12:58 am

Steve,
Are these tubes made of Pyrex or soft glass?

Darryl

Panrock · 3rd Nov 2007, 12:00 pm

AFAIK soft glass.

S

ppppenguin · 3rd Nov 2007, 12:06 pm

AFAIK, the only common Pyrex CRTs in the UK were the pre-war EMI tubes such as the 6/6. I think Baird also made some Pyrex CRTs.

Panrock · 3rd Nov 2007, 2:27 pm

You'll find his web site here

http://www.tube-cathodique.com

It's in French, though if you have a serious inquiry for business you can email him in English.

He is situated in the south of France, so it's not just a run over by ferry in the car.

The price will depend on what the work includes and the cost of transport...we're talking the low hundreds of pounds.

Steve

ppppenguin · 3rd Nov 2007, 2:42 pm

Looking at the pictures on his site it's a far bigger operation than Display Electronics of Uxbridge who were the last surviving UK rebuilder. The place looks a lot cleaner and nicer too. Display Electronics looked like a dump in a shed. This does them a disservice because they did excellent work. Look at my article A Vintage Tube Renovation on the publications page of my website. The photo in that article doesn't really show much of the premises but it's clearly not all bright and sparkling.

ppppenguin · 3rd Nov 2007, 3:39 pm

I think we need a separate thread that pulls together all the CRT rebuild resources. There aren't many rebuilders! One in France, one in the USA...... any more? AFAIK nobody can do pyrex (hard glass) tubes at the moment.

I suspect these companies make their living from radar and military customers. Domestic receiver tubes can only be a sideline at best.

The new CRT market is dying very fast now. Residual production of TVs and computer monitors, probably some 'scope tubes and other more specialised devices such as flying spot scanners. Colour reciver tubes in particular can only be economically made in huge numbers. I think the whole business will be all but dead within 10 years and that's being optimistic.

Please don't turn this thread into a CRT/LCD/plasma discussion!

ppppenguin · 4th Nov 2007, 10:04 pm

Quote:

Originally Posted by ppppenguin

.... Display Electronics looked like a dump in a shed. This does them a disservice because they did excellent work. Look at my article A Vintage Tube Renovation on the publications page of my website. The photo in that article doesn't really show much of the premises but it's clearly not all bright and sparkling.

I've found a better copy of the photo from that 1987 article. Definitely looks like a shed with a tin roof

The man is Charlie Bradley, a skilled glassblower who worked on CRTs at EMI before the war. I rather assume that Charlie is no longer of this world. He'd be in his late 90s if he was. The CRTs are a modern-ish colour tube and an Emiscope 6/6 partway through rebuilding. The gun has been removed and the tube rough pumped and resealed. It's not obvious that the graded seal between the pyrex of the tube and the soft glass of the new pinch has been done. This is a very skilled bit of glassblowing. The 6/6 gun assembly is sitting between the 2 CRTs.

Brian R Pateman · 4th Nov 2007, 10:53 pm

Jeffrey,

Thank you for posting that picture. I had many tubes rebuilt by Charlie.

It was always a pleasure to go up to Uxbridge to collect from Display Electronics. My shops were closed on a Wednesday afternoon in the good old days of early closing. Worthing to Uxbridge made a pleasant trip out and there was always something of interest to see in the ramshackle collection of tin roofed sheds.

I had about 300 sets out on rental so the re-built tube was a vital part of my business plan!

Regards,

Steve_McVoy · 8th Nov 2007, 2:34 am

As far as rebuilding the hard glass tubes, we almost got it done. Clinton electronics, another rebuilder in the U.S., succeeded in attaching a replacement tubing to the old shell, but was unable to find a stem for mounting the gun that had the same characteristics as the other glass. A custom stem would cost $5,000, which is not an insurmountable figure if there are enough prewar tubes that could be rebuilt. The experiments were done with a 12AP4, which has a neck diameter very similar to the 35mm necks of the British prewar tubes.

I am still pursuing this, and if there is enough interest from collectors, we may go ahead with the project.

2nd Nov 2007, 10:02 pm	#1
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,532	Re-gunned CRM121 tubes Just a note to say I spent much of yesterday trying out various CRM121's and a CRM123 which had been re-gunned by Philippe in France - on a Baird Townsman. I have to observe confidentiality as to who are holding these particular examples but I can vouch for their quality. This should give us a lot of hope for the future. Steve __________________ https://www.radiocraft.co.uk

3rd Nov 2007, 12:58 am	#2
tubesrule Hexode Join Date: Jul 2004 Location: Michigan USA Posts: 325	Re: Re-gunned CRM121 tubes Steve, Are these tubes made of Pyrex or soft glass? Darryl

3rd Nov 2007, 12:00 pm	#3
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,532	Re: Re-gunned CRM121 tubes AFAIK soft glass. S __________________ https://www.radiocraft.co.uk

3rd Nov 2007, 12:06 pm	#4
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Re-gunned CRM121 tubes AFAIK, the only common Pyrex CRTs in the UK were the pre-war EMI tubes such as the 6/6. I think Baird also made some Pyrex CRTs.

3rd Nov 2007, 2:27 pm	#5
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,532	Re: Re-gunned CRM121 tubes You'll find his web site here http://www.tube-cathodique.com It's in French, though if you have a serious inquiry for business you can email him in English. He is situated in the south of France, so it's not just a run over by ferry in the car. The price will depend on what the work includes and the cost of transport...we're talking the low hundreds of pounds. Steve __________________ https://www.radiocraft.co.uk

3rd Nov 2007, 2:42 pm	#6
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Re-gunned CRM121 tubes Looking at the pictures on his site it's a far bigger operation than Display Electronics of Uxbridge who were the last surviving UK rebuilder. The place looks a lot cleaner and nicer too. Display Electronics looked like a dump in a shed. This does them a disservice because they did excellent work. Look at my article A Vintage Tube Renovation on the publications page of my website. The photo in that article doesn't really show much of the premises but it's clearly not all bright and sparkling.

3rd Nov 2007, 3:39 pm	#7
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Re-gunned CRM121 tubes I think we need a separate thread that pulls together all the CRT rebuild resources. There aren't many rebuilders! One in France, one in the USA...... any more? AFAIK nobody can do pyrex (hard glass) tubes at the moment. I suspect these companies make their living from radar and military customers. Domestic receiver tubes can only be a sideline at best. The new CRT market is dying very fast now. Residual production of TVs and computer monitors, probably some 'scope tubes and other more specialised devices such as flying spot scanners. Colour reciver tubes in particular can only be economically made in huge numbers. I think the whole business will be all but dead within 10 years and that's being optimistic. Please don't turn this thread into a CRT/LCD/plasma discussion!

4th Nov 2007, 10:53 pm	#9
Brian R Pateman Nonode Join Date: Jun 2005 Location: Western Lake District, Cumbria (CA20) - UK Posts: 2,136	Re: Re-gunned CRM121 tubes Jeffrey, Thank you for posting that picture. I had many tubes rebuilt by Charlie. It was always a pleasure to go up to Uxbridge to collect from Display Electronics. My shops were closed on a Wednesday afternoon in the good old days of early closing. Worthing to Uxbridge made a pleasant trip out and there was always something of interest to see in the ramshackle collection of tin roofed sheds. I had about 300 sets out on rental so the re-built tube was a vital part of my business plan! Regards, __________________ Brian

8th Nov 2007, 2:34 am	#10
Steve_McVoy Pentode Join Date: Feb 2004 Location: Columbus, Ohio, USA Posts: 150	Re: Re-gunned CRM121 tubes As far as rebuilding the hard glass tubes, we almost got it done. Clinton electronics, another rebuilder in the U.S., succeeded in attaching a replacement tubing to the old shell, but was unable to find a stem for mounting the gun that had the same characteristics as the other glass. A custom stem would cost $5,000, which is not an insurmountable figure if there are enough prewar tubes that could be rebuilt. The experiments were done with a 12AP4, which has a neck diameter very similar to the 35mm necks of the British prewar tubes. I am still pursuing this, and if there is enough interest from collectors, we may go ahead with the project.