Bell 1A

[Iannacconeg]

Hi all
I know from my research that GPO candlestick 150 can only use a Bellset 1 and must not be used with a bell 1A as they don't have an induction coil.
I opened my base to check the wiring and found a phone circuit diagram inside it. It's original and to my surprise it shows the candlestick connecting to a bell 1A
Eh?
Gerardo

[OscarFoxtrot]

An extension telephone with bell, using the induction coil in a bellset at the main telephone?

[Dave Moll]

Any chance of uploading an image of that diagram? This may give some idea how it should be connected.

[els1967]

The second diagram down shows the phone connections with a bellset 1a.

http://www.samhallas.co.uk/repositor.../0000/N250.pdf

[ThePillenwerfer]

All the diagrams on N250 show a Bellset No 1 or Bellset No 25. The bell assembly, ie the bit that actually make a noise, is a 1A or 59A but that's only a component of the whole.

[Pellseinydd]

Originally Posted by els1967

The second diagram down shows the phone connections with a bellset 1a.

http://www.samhallas.co.uk/repositor.../0000/N250.pdf

Not quite!! It says 'Bell 1A unmounted' which is but one of the components inside the 'Bellset No 1' which is quoted on the otherside of the 'bell mechanism symbol' in the circuit.

I can never remember seeing a Tele 150 used with just a 'Bell 1A' (i.e. the version mounted in a square woodn case) during my days with the GPO in the 1950's and 60's. There would have to be a capacitor in the circuit somewhere otherwise the line would be permanently 'looped'.

I can't see a 'Bell 1A' being shown on a diagram inside a 'candlestick' phone as it wasn't a standard setup with a candlestick. I can find a Bell 1A shown on a few early N diagrams wired to a candlestick such as a Tele 124 as an extension bell on an extension phone on a Plan 1 arrangement (N1476 dated 1922 - not on Sam Hallas' website - I have lots of early ones acquired in 1960)

It will be interesting to see the diagram from in the telephone?

[keithinuk]

I was under the impression that the 1A was just an extension bell, as I have three or four about somewhere, just fitted with the bell coils inside and nothing else.

[Pellseinydd]

Originally Posted by keithinuk

I was under the impression that the 1A was just an extension bell, as I have three or four about somewhere, just fitted with the bell coils inside and nothing else.

You're correct in your assumption. The confusion can come from the fact that the GPO had two 'items' - the first is known as a 'Bell 1A unmounted' which is purely the bell mechanism (magnet coils, hammer, gongs etc) and the other (more common) one is a 'Bell 1A' which consists of a square wooden box/case with a 'Bell 1A unmounted' fitted in it with the gongs above. It was used purely as an extension bell.

Another part of the problem is that modern 'dealers/sellers' fit a candlestick phone with a modern lead connected to a 'Bell 1A' fitted with a PSTN lead and described it as a 'Bellset 1A'. There never was a 'Bellset 1A' !!. Note the GPO designated it as a 'Bellset ...' if there was more than just a bell in it. Otherwise it was known as a 'Bell ..' For instance there was a unit identical to the 'Bell 1A' but also fitted with a 2uF capacitor and it was known as a 'Bellset No 8' - I have one with my 1913 Telephone No 72 candlestick also fitted with a Dial No 1. That combination never used an induction coil!

[Graham G3ZVT]

This one apparently started life as a Bell No.1 and ended up as a Bellset No.41

https://tinyurl.com/y7putnmn

What's the difference between a 1 and a 1A?

[Dave Moll]

Whereas Bell 1A is, as described above, just a bell, Bellset 1 also contains the circuitry (including induction coil and capacitor) to allow a pillar telephone (without these components) to be used on a telephone line.

[Pellseinydd]

Originally Posted by rambo1152

What's the difference between a 1 and a 1A?

99% of 'Bellset No 41' were converted from 'Bellset No 1' units. The reason? The Tele 310 was introduced around 1947 for use on 'Shared Service, Separate Metering' lines (party lines). With two telephones across the same line but at different locations, a way had to be found to prevent 'bell tinkle'. This was achieved by using a 'slow to operate' relay which didn't respond to the small 'spikes' which caused the bell tinkle. As there was no room for the relay in the telephone and there were plenty of Bellsets No 1 being returned as candlesticks were replaced by 300 type phones, the good old 'green' GPO recycled them in BS 41's. However by the end of 1949, a little component had become available - Thermistor 1A' which could replace the relay and fit into a telephone. Hence the Telephone 312 came into being. Most Tele 310's were converted to Tele 312's making thousands of Bellsets 41 spare. Hence the reason why there are plenty of Bellsets 41 about and Tele 310's are quite rare .