Dating an old western electric telephone
Reflecting the progress of automatic switching, the dial operated the automatic exchange switching mechanism by sending out a series of electrical impulses corresponding to the number being dialled. The transmitter head to the right is the older style solid backed 'Transmitter No. In Australia these refurbished telephones were known as Type 138.It was no longer necessary for the operator to connect all calls. 150 was still connected to a manual exchange, the space in the base of the telephone for the dial was covered by a dummy insert (used as a number label holder) which could be replaced by a dial when the exchange went automatic. In consequence a telephone with its original solid back transmitter is relatively rare item. Ron Kay notes that some collectors there assume that their Western Electric style candlestick is a Siemens phone because the new replacement microphones have the name Siemens Brothers moulded on the bakelite mouthpiece.I was lead to believe it was a compound of India rubber and weak mix of the Bakelite compounds giving a flexible (only slightly) but hard to the touch material that could be deformed by mild heating. These Bellsets include an induction coil which is an essential part in the transmission circuit. Ever noticed how the earpiece covering peels off, sad isn't it. "F" is the type (designation) of hook there were also Z and AB as I recall.Question: Should the Bakelite earpiece cap have a notch moulded on to the face and why is it there on some and not others?
If you've got some electronics related questions, this is the place to come.Please join our friendly community by clicking the button below - it only takes a few seconds and is totally free. 150L was introduced, which superseded the Telephone No. Similar to earlier telephones in that it was a candlestick model, it was innovatory in introducing the dial to most subscribers for the first time. Variants: The solid-back microphones originally fitted were mostly replaced with a Bakelite moulding containing a standard carbon microphone inset (these assemblies were made by Siemens Brothers).Answer: That's how it was done in the factory but don't forget to HMP grease and cover the thread on the tube. Question: How do you remove the Bakelite grommet on the base in one piece?Answer: Its not Bakelite, its a hard rubber compound.