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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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21st Jan 2019, 3:21 pm | #1 |
Octode
Join Date: Oct 2011
Location: Wrexham, North Wales, UK.
Posts: 1,457
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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. |
21st Jan 2019, 3:31 pm | #2 |
Hexode
Join Date: Dec 2018
Location: Sheffield, South Yorkshire, UK.
Posts: 364
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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
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21st Jan 2019, 9:27 pm | #3 | |
Heptode
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
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Re: GPO 1A bell. Advice sought.
Quote:
See http://www.britishtelephones.com/adjacbel.htm for GPO documents on adjusting bells Ian CNet - Mold (0352) 2979 MR ETD 053-6278 |
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21st Jan 2019, 10:20 pm | #4 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
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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.
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-- Graham. G3ZVT Last edited by Graham G3ZVT; 21st Jan 2019 at 10:37 pm. |