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 26th Sep 2021, 10:12 pm   #1
marrold
Triode
 
Join Date: Aug 2021
Location: Watford, Hertfordshire, UK.
Posts: 10
Default GEC 746 with high impedance ringer.

Hi all,

I picked up a cheap 746 at RetroTech today and took the shell off to reveal it's not a "standard" 746, as it has 2x 1.25K coils on the ring with a capacitor inbetween, and two seemingly random 3.3K resistors attached to spare terminals. It also has an additional hook switch.

Does anyone know the story with this one?
Attached Thumbnails
Click image for larger version

Name:	20210926_221039.jpg
Views:	132
Size:	45.0 KB
ID:	242190   Click image for larger version

Name:	20210926_150010.jpg
Views:	129
Size:	54.5 KB
ID:	242191   Click image for larger version

Name:	20210926_145741.jpg
Views:	124
Size:	67.1 KB
ID:	242192   Click image for larger version

Name:	20210926_211418.jpg
Views:	136
Size:	65.5 KB
ID:	242193   Click image for larger version

Name:	20210926_145816.jpg
Views:	114
Size:	78.3 KB
ID:	242194  


Last edited by marrold; 26th Sep 2021 at 10:19 pm.
marrold is offline  
Old 30th Sep 2021, 12:35 pm   #2
dagskarlsen
Heptode
 
dagskarlsen's Avatar
 
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 640
Default Re: GEC 746 with high impedance ringer.

The extra hook sw. and the high impedance ringer may be needed to be approved in some countries that had their own rules, I see absolutely no reason for those 3k3 resistors. Maybe it was relevant for some shared line systems to indicate who that should be billed for what?
dagskarlsen is offline  
Old 30th Sep 2021, 11:35 pm   #3
winston_1
Hexode
 
Join Date: Oct 2012
Location: London, UK.
Posts: 497
Default Re: GEC 746 with high impedance ringer.

Quote:
Originally Posted by dagskarlsen View Post
I see absolutely no reason for those 3k3 resistors. Maybe it was relevant for some shared line systems to indicate who that should be billed for what?
They are shown in the circuit on the paster.
winston_1 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 12:03 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.