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 Jan 2019, 3:21 pm   #1
Glowing Bits!
Octode
 
Glowing Bits!'s Avatar
 
Join Date: Oct 2011
Location: Wrexham, North Wales, UK.
Posts: 1,457
Default GPO 1A bell. Advice sought.

I have recently got hold of the above bell unit from, ahem, ebay. The cabinet was already fully restored and even re-wired for modern systems. It does work, in a fashion anyhow (at least the coils work) but has had to have maintenance performed while following a very good online tutorial in step by step format.
Here goes the maintenance, the pivot was the first thing to tighten up, the armature gaps have been checked but required no adjustment, here comes the slight issue, the hammer strikes one side a bit too far but is not going over to the other side, it looks central by then.
Something does not look right with one of the mounting arrangements for one of the coils, the following pics form part of what's wrong, please could someone tell me what looks right or wrong in the pics, thanks.
Rick.
Please note in pic 4, is one coil supposed to have a biting washer there? It looks suspicious.
Attached Thumbnails
Click image for larger version

Name:	20190121_132201.jpg
Views:	107
Size:	47.7 KB
ID:	176834   Click image for larger version

Name:	20190121_132217.jpg
Views:	106
Size:	70.9 KB
ID:	176835   Click image for larger version

Name:	20190121_132307.jpg
Views:	100
Size:	42.0 KB
ID:	176836   Click image for larger version

Name:	20190121_132401.jpg
Views:	105
Size:	47.3 KB
ID:	176837  
Glowing Bits! is offline  
Old 21st Jan 2019, 3:31 pm   #2
BRASSBITS
Hexode
 
Join Date: Dec 2018
Location: Sheffield, South Yorkshire, UK.
Posts: 364
Default Re: GPO 1A bell. Advice sought.

The bells are adjustable, the hole in the bells are offset so just slacken the nut and turn the bell till its in striking distance then tighten nut
BRASSBITS is offline  
Old 21st Jan 2019, 9:27 pm   #3
Pellseinydd
Heptode
 
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
Default Re: GPO 1A bell. Advice sought.

Quote:
Originally Posted by BRASSBITS View Post
The bells are adjustable, the hole in the bells are offset so just slacken the nut and turn the bell till its in striking distance then tighten nut
When the 'hammer' is on one side or the other, there should be a very slight gap between the hammer and the gong. This allows the gong to continue vibrating after it has been hit by the hammer. But don't have the gap too great or the hammer will not hit the gong whilst it is swinging from side to side
See http://www.britishtelephones.com/adjacbel.htm for GPO documents on adjusting bells

Ian
CNet - Mold (0352) 2979
MR ETD 053-6278
Pellseinydd is offline  
Old 21st Jan 2019, 10:20 pm   #4
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: GPO 1A bell. Advice sought.

I suggest you re-assemble it, and slacken off the gongs and rotate them for best ring. As Brassbits said, they're deliberately off-centre so you can adjust the striking distance.

If you compare it with my 1A, yours has a biasing leaf-spring missing under one side of the armature. I doubt if it makes much difference in practice, but Ian will tell us.
Attached Thumbnails
Click image for larger version

Name:	1a.jpg
Views:	74
Size:	106.4 KB
ID:	176869  
__________________
--
Graham.
G3ZVT

Last edited by Graham G3ZVT; 21st Jan 2019 at 10:37 pm.
Graham G3ZVT is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 11:30 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.