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Old 24th Sep 2018, 12:52 pm   #1
kevinhalf
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Default Old telephone won't ring

Hi there,

I hope I am posting this in the appropriate place.
I have a 1981 British dial telephone, which works fine but does not ring (here in Belgium). Apparently the voltage on the Belgian phone network is too low. Is it possible to 'boost' it somehow?

Many thanks,

Kevin
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Old 24th Sep 2018, 2:00 pm   #2
Dave Moll
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Default Re: Old telephone won't ring

Are you sure it's a matter of line voltage? It may be that ringing is via a third wire (usually coloured blue if the line wires are red and white). The ringing voltage is applied to this wire via a capacitor of up to 1.8μF from the "B" leg (usually red) of the line. In the UK this is achieved either by use of a master socket containing the appropriate components or by an ADSL microfilter (most UK ones including a ringer capacitor).
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Old 24th Sep 2018, 2:17 pm   #3
kevinhalf
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Default Re: Old telephone won't ring

Thank you, Dave. So It may down to the socket then? The ringer does work because it was tested in the antiques shop the other week when I bought it. All I've done is plug the original phone plug into an adapter that fits the Belgian wall socket.
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Old 24th Sep 2018, 3:16 pm   #4
Nickthedentist
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Default Re: Old telephone won't ring

Please post a picture of the insides of the phone, showing how the wires are connected to the circuit board.

Nick.
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Old 24th Sep 2018, 4:14 pm   #5
kevinhalf
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Default Re: Old telephone won't ring

Thanks.
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Old 24th Sep 2018, 5:43 pm   #6
TonyDuell
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Default Re: Old telephone won't ring

That looks like a Telephone 746 or 8746, and since there are no connections to terminals T7 and T9, you do need an external ringing capacitor.

There are 2 things you could try :

1) Disconnect the blue wire of the line cord. Connect terminal T9 to T8 (leaving the existing wiring on T8 alone) and T7 to T6 (again leaving the existing wiring and jumpers alone).

2) Get a UK _Master_ telephone socket. Connecter terminals 2 and 5 inside the socket to your telephone line. Plug the UK telephone in (without changing any internal wiring).
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Old 24th Sep 2018, 6:29 pm   #7
Dave Moll
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Default Re: Old telephone won't ring

Quote:
Originally Posted by TonyDuell View Post
1) Disconnect the blue wire of the line cord.
If you go for this option, you could park it on one of the unused terminals from T11 to T14.
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Old 24th Sep 2018, 7:30 pm   #8
Euros1951
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Default Re: Old telephone won't ring

TRY:-
http://www.telephonesuk.co.uk/conversion.htm
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Old 24th Sep 2018, 9:08 pm   #9
Dave Moll
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Default Re: Old telephone won't ring

I think in this instance the problem is that it is converted for three-wire working and needs to be reverted to the original two-wire state.
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Last edited by Dave Moll; 24th Sep 2018 at 9:12 pm. Reason: reworded for clarification
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Old 24th Sep 2018, 9:47 pm   #10
Nickthedentist
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Default Re: Old telephone won't ring

yes, quite. Has anyone got a pic of the original configuration?
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Old 25th Sep 2018, 4:33 am   #11
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Default Re: Old telephone won't ring

I haven't got a picture but here's a diagram.
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Old 25th Sep 2018, 7:08 am   #12
dagskarlsen
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Default Re: Old telephone won't ring

Hi
As you understand the GB wiring standard is different than most other countries, that makes rewiring or converting a common issue. For us non GB people it will sometimes include adding parts as a capacitor who has the function of just letting ring current pass to the ringer. In GB plug and socket system the capacitor is located in the socket.

Your phone may have the capacitor, or may not. First try should be to put a wire or link between T6- and T7 and try. You also need connections between T9-T9 (missing on picture) and between T16-T17-T18-T19 (looks right on the picture)

Give it a try.
The Belgian ringing voltage should be at least 60V and that should be enough.
(It may be 90 as in GB too)

dsk
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Old 25th Sep 2018, 10:22 am   #13
kevinhalf
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Default Re: Old telephone won't ring

Thank you guys. I wired it according to the diagram - the green and red were already in place - but still no jolly ringing.

Kevin
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Old 25th Sep 2018, 11:45 am   #14
Dave Moll
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Default Re: Old telephone won't ring

I think a photo of how you now have it wired would be helpful, so that we can check that everything is correct.

Also, if you have a multimeter, it would be a good idea to check the resistance of the bell motor (T4 to T16), which should be approximately either 1,000Ω or 4,000Ω (depending on its age).
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Old 25th Sep 2018, 3:22 pm   #15
kevinhalf
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Default Re: Old telephone won't ring

Thanks. I believe it dates from 1981.
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Old 25th Sep 2018, 8:37 pm   #16
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Default Re: Old telephone won't ring

Hi, the first thing you need to do is to ensure that there is a capacitor in the C1 position next to the gravity switch at the right of the phone looking from the rear (it looks like it is present from your picture)

Assuming that you are using some kind of adapter to allow you to use a British BT plug on your country's phone socket re-wire/strap the phone as follows.

Strap T4 - T5 - T6 - T7
Strap T8 - T9
Strap T16 - T17 - T18 - T19

If you don't have enough straps you can just use wire links

Park the Green and Blue leads of your line cord on T14 and T15 (it doesn't matter which way round they are)

Red of line cord to T8

White of line cord to T18

Try that and let us know

Regards

Andrew
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Old 25th Sep 2018, 9:07 pm   #17
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Default Re: Old telephone won't ring

Have you a multimeter? Can you actually measure the a.c. voltage on the bell coils when it's meant to be ringing? What's to say the bell hasn't gone O/C or simply developed a mechanical fault between it ringing successfully earlier and now? Or you have a duff adaptor?

Is the hammer and armature free to move?
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Old 25th Sep 2018, 9:53 pm   #18
ThePillenwerfer
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Default Re: Old telephone won't ring

You need to join T6 and T7 together and T9 to T10. You don't need proper 'straps;' bits of wire or paper-clips will do. Other than that it looks right.

I've marked what I mean in red on your picture.

By the way, it's 1979 vintage. There does indeed seem to be a capacitor (the white block) in the C1 position in your photograph in Post 5.
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Last edited by ThePillenwerfer; 25th Sep 2018 at 10:11 pm.
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Old 26th Sep 2018, 9:47 am   #19
Dave Moll
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Default Re: Old telephone won't ring

Quote:
Originally Posted by ThePillenwerfer View Post
You need to join ... T9 to T10.
That should read "T8 to T9" - as shown in the photo.

By the way, it may be a good idea to point the spade on the blue linecord lead the other way so that avoids the risk of fouling the connections on the row above.
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Last edited by Dave Moll; 26th Sep 2018 at 9:52 am. Reason: blue lead
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Old 26th Sep 2018, 10:50 am   #20
kevinhalf
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Default Re: Old telephone won't ring

Marvellous. Thank you so much, gentlemen, ThePillenwerfer's solution works. It's not as loud as the ring in the UK but still quite audible. I didn't have anything as technical as a paper clip here to do the strapping but a piece of old guitar string has done the trick.
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