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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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21st Sep 2021, 10:01 pm | #1 |
Pentode
Join Date: May 2011
Location: Enniskillen, Fermanagh, UK.
Posts: 188
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GPO telegraph sig & galvanometer
I have a galvanometer in very poor condition, which I would like to clean up. Internet gives it different names, " Differential Galvanometer ", " Cathedral signal indicator ", "Type 22a". This one has center zero with 60 to either side. Any experience on how to dismantle and how it was used, of interest.
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22nd Sep 2021, 12:47 pm | #2 |
Heptode
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 663
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Re: GPO telegraph sig & galvanometer
Normally there is a thumbscrew on the back near the top. Remove it and the hood with the glass in it can be carefully tilted forwards, this is located by 2 pins on the base section.
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23rd Sep 2021, 2:01 pm | #3 |
Pentode
Join Date: May 2011
Location: Enniskillen, Fermanagh, UK.
Posts: 188
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Re: GPO telegraph sig & galvanometer
Hello Gridiron, thank you for reply and yes I had done that. So that is how I knew to ask for help. As the needle/pointer is stuck, the small screws really tight and the pivot, near pocket-watch delicate, I hesitate to proceed. In the past GPO telephones had engineering instruction for dismantling/calibrating such things, even with exploded views.
How the ( telegraph ? ) line was connected ( from underneath ? ) and it's intended use also of interest. many thanks . Cliff. |