746F ringer problem - please help!

[CosmicMia]

Hi There Folks

I am the very proud owner of a red 1971 version of the above and to date it has been working beautifully.

However, a few days ago, it just stopped making it's usual lovely bring-bring ring when someone called and now gives out just one long continuous ring which makes it sound like one of those horrible alarm clocks you want to chuck across the room!

I've never owned a vintage phone before and am not a complete technophobe but would need guidance on how to correct this problem in girlspeak (or laymans terms so as not to be sexist )

I would be very grateful for any advice as I don't want to part with either my phone, or my friends and family because I'm so grumpy when I answer their calls!!!

[russell_w_b]

Originally Posted by CosmicMia

However, a few days ago, it just stopped making it's usual lovely bring-bring ring when someone called and now gives out just one long continuous ring which makes it sound like one of those horrible alarm clocks you want to chuck across the room!

Hello Cosmic Mia,

When you say 'one long continuous ring', do you mean when you are signalled to an incoming call? It sounds like your exchange ringing-cadence has changed for whatever reason. The 'traditional' ringing cadence is 400 milliseconds on - 200 milliseconds off - 400 milliseconds on, then repeated.

Can you plug another telephone in to your socket and see how that rings?

Or...

Confirm your 700 series instrument rings properly by trying out on another line?

[Dave Moll]

Just to clarify what you're saying - it doesn't ring constantly all the time it's plugged in, just on receipt of an incoming call? Given that the ringer is responding directly to the pulses of ring current sent down the line (known in "technospeak" as the ringing cadence), I'm puzzled how it continues to ring during the gaps in that signal.

edit: I notice that Russell posted while I was editing.

[AndiiT]

Originally Posted by russell_w_b

Can you plug another telephone in to your socket and see how that rings?

Or...

Confirm your 700 series instrument rings properly by trying out on another line?

I would be inclined to try the above suggestions in the first instance, your fault does sound like a fault at the exchange end though.

Regards
Andrew

[Tim]

I'm puzzled how it continues to ring during the gaps in that signal.

......unless something is breaking down(becoming electrically leaky)-ringing volts are higher than line volts-possible faulty/damp socket(or extension wiring) or ringing capacitor in your phone. I have occasionally come across phones exhibiting these symptoms with flashover on the PCB. I had this fault once when an extension cable was impaled on a carpet gripper spike.

Ring 151 and get BT to test your line.

[OscarFoxtrot]

A shorted ringing capacitor can cause electronic ringers to ring because they respond to the DC line voltage, which is continuous, as well as the AC ringing voltage which is cadenced.

However magneto bells don't respond to DC.

[russell_w_b]

Originally Posted by OscarFoxtrot

However magneto bells don't respond to DC.

Indeed. Some incorrect internal wiring crossovers on the subs side of the master LJU can send 50V d.c. through the electronic ringers, which, of course, are unable to differentiate between 50V d.c. and 75V RMS 25Hz a.c. being north of a bridge-rectifier.

But a magneto bell needs a.c. from 25 - 80V at 17 - 30Hz to work at all (50Hz with adjustment of a type 59A bell). This sort of signal must be definitely sent from the exchange.

No 230V a.c. mains on your telephone line, is there?

[val33vo]

Sounds like an exchange fault to me, probably a system Y faulty line card in the telephone exch ( system X was much more reliable ) however check by substitution before you call OPENREACH / BT or your telecoms provider otherwise the bill will give you a nasty shock if it turns out to be your equipment / wiring, the engineers are actively targeted to bill customers where ever appropriate