Telephone repair

Retro6

Retro6

Retro6

Associate
Joined
30 Jan 2019
Posts
953
I know there will be a lot of people who don't use there landlines anymore but I still use mine and I like retro telephones. I've repaired/converted a good number of Bakelite and GPO rotary dial telephones in my time but with automated telephone services today rotary telephones are not much good anymore when you need to press numbers so the next best thing are the old push button telephones. The modern ones are crap and don't last long where as the old ones are better made and last for years and years.

I bought a nice old telephone push button BT telephone from a boot fair and I paid 7 pound for it because I was desperate at that moment in time where I needed a push button telephone to make some calls. The lady who I bought it from said it works but when I got it home and tested it, it was completely dead. I opened it up and I saw it had some liquid, possibly coffee had been spilled on it or something so I got out my IPA and a toothbrush and cleaned up the keypad and the circuit boards and then I plugged it in not expecting much and I got a dial tone and a responsive keypad... so I put it all back together and its been working ever since with no problems. The clarity is amazing on older phones when making and receiving calls.

I needed an extra telephone for another room and today I found another nice old push button telecom phone. It looks nice. I was told its working blah blah blah same story... bought it back home and tested it, it has a dial tone, but the keypad isn't functioning so I've got it apart, I've cleaned the circuit boards and keypad plus keypad parts with IPA and the keypad sort of works now I was able to dial out on it... just abouts... there is no keypad tone, having no keypad tone makes is hard to tell which buttons are working, so I need to find out why the there is no keypad tone also there are black pads on the keypad membrane that might be a bit worn... but first I need to make sure the electronic side of things are working as they should.

Does anybody know what electronic components I should be looking at for the keypad tones?
 
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Push button phones work by combining pairs of tones to create the signal per button push. There are loads of potential component combinations that can do this in an analogue format so you will probably have to troubleshoot around the components inside the phone, taking note of data on the components inside the phone (or if you have the phone model number you may be able to get a circuit diagram which would help a lot).
 
My first memory of a landline phone was one of these bad boys.

https://flic.kr/p/2pLwazR

My mum had to get a locking device which attached to the rotary thing to stop us using the phone and generating sky-high bills!

Feek said:
Wasn’t that pre dtmf? It would have generated dialling pulses rather than tones.
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Yes! I remember the patterns of clicks you'd hear on the line when you dialled a number.
 
FBi7 said:
My first memory of a landline phone was one of these bad boys.

https://flic.kr/p/2pLwazR

My mum had to get a locking device which attached to the rotary thing to stop us using the phone and generating sky-high bills!


Yes! I remember the patterns of clicks you'd hear on the line when you dialled a number.
Click to expand...
Excellent phones and fully serviceable. I have lots of these plus lots of bell sets and lots of spare boards still sealed in the packaging. I installed an old GPO bellset in my hallway which has been working nicely for years. Unfortunately these phones don't fetch much like they did around 2007/2012'ish. The value went right down on these so fast. They only fetch about 25 quid now in fully working order.

The money is in the Bakelite phones, I've got one from the 1930s all working but in those days you didn't have the rotary dial, to make a call back then you had to use the hook switch for the operator. I have a couple from the 1940s as well. I'll never sell those ones.
 
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5068A414-D449-43DB-8A96-601879D7220C_1_105_c_1024x1024@2x.jpg
 
I got the phone back together, there isn't much I can do. Electronically, everything is functional and working as it should but the keypad membrane I suspect is worn out hence the keypad being temperamental.
 
Raymond Lin said:
Back in Hong Kong we had one of those really old phones where you turn the dial and the rotation back to reset its position is how it dials. It literally would take about a minute to dial all the digits. When we got a button phone it felt like some kind of magic lol
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Top fact that's why 999 is 999. It was the least likely voltage to be miss understood.
 
Retro6 said:
I got the phone back together, there isn't much I can do. Electronically, everything is functional and working as it should but the keypad membrane I suspect is worn out hence the keypad being temperamental.
Click to expand...
I'm sure I've seen YouTube videos on computer repairs, where the worn carbon contacts on the keyboard membrane are replaced with sort of foil. I could be wrong though.
 
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