UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Telephony and Telecomms

Notices

Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

Closed Thread
 
Thread Tools
Old 21st Feb 2020, 12:04 am   #1
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
Default GPO 706, when was the change from Diakon to ABS?

Hello everyone,

As many of us know, the GPO's model 706 phone, introduced 1959/60, was originally produced with cases made from Diakon (i.e. PMMA, poly-methyl-methacrylate, the same stuff as acrylic dentures are made from!). These don't seem to fade in the sun much, have a lovely "glassy" quality to them, but break easily if dropped. The difference is most obviously seen in the "ivory" coloured sets, the PMMA and ABS variantq looking very different from one another after 60-odd years.

Later, ABS was used instead, which was the material the later 746 cases too.

Does anyone know when this change took place? Was it with all the manufacturers? And were older, Diakon cases replaced with ABS when instruments were factory refurbished, as a matter of course?

Cheers,

Nick.
Nickthedentist is offline  
Old 17th Mar 2020, 12:12 pm   #2
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
Default Re: GPO 706, when was the change from Diakon to ABS?

Not exactly answering my own thread, but I've read on Bob Freshwater's site that you can tell the material used from codes moulded into the plastic:

12 = Diakon (PMMMA, Perspex)

17 = ABS


Nick
Nickthedentist is offline  
Old 17th Mar 2020, 9:43 pm   #3
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
Default Re: GPO 706, when was the change from Diakon to ABS?

More Googling has got me the answer... https://www.britishtelephones.com/t706case.htm

Ans. = very early 1963.

Last edited by Nickthedentist; 17th Mar 2020 at 9:52 pm.
Nickthedentist is offline  
Old 24th Mar 2020, 2:54 pm   #4
russell_w_b
Dekatron
 
russell_w_b's Avatar
 
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,684
Default Re: GPO 706, when was the change from Diakon to ABS?

Quote:
Originally Posted by Nickthedentist View Post
More Googling has got me the answer... https://www.britishtelephones.com/t706case.htm
That's interesting, Nick.

My Ericsson N1901A PAX or export instrument very clearly shows a stamp 5/5 12 beneath the flat bit behind the handset rest and the thickness of the case suggests it's Diakon. But my 1961 Plessey GPO 706 Mk:2 instrument has a different marking, this time behind the front of the case below the dial, and it says BLD17, suggesting ABS. Yet the cases are the same thickness, feel and finish.

The marking inside the earpiece on the Ericsson is also 5/5 12 but on the Plessey is APB12 (A. P. Besson?) and a No:26, being, I think, the type of GPO designated earpiece.

Maybe early ABS cases were the same thickness as Diakon? It's like unravelling the Dead Sea Scrolls!
__________________
Regds,

Russell W. B.
G4YLI.
russell_w_b is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 8:13 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.