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Old 14th Mar 2017, 7:02 pm   #1
YoungManGW
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Default 746 Telephone Problem

I have a K6 telephone kiosk in the garden. When I installed it I ran an extension cable from the kiosk to the house telephone socket. Using a splitter, both the 746 telephone in the K6 and the normal modern house phone are connected to the same socket.

When the house phone rings, the 746 in the K6 does so too, albeit very faintly. When I pick up the receiver of the 746, though, it is not possible to hear the caller. On the house phone there's no problem. Also, the 746 gives a dialling tone when its receiver is lifted, but it's impossible to place a call - the line gives the dead tone after the first few digits.

I wondered if the issue might lie in the extension lead simply being too long, whether there might be some limit to how long such a lead can be. That connecting the 746 to the house socket is probably about 60 feet long. Could this be the problem?

Or is the problem more likely to be one of incorrect wiring?

Any assistance would be much appreciated. Many thanks.

Regards,
Richard
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Old 14th Mar 2017, 7:27 pm   #2
julie_m
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Default Re: 746 Telephone Problem

Can you move the 746 from the phone box and plug it in in the house? That would confirm if or not the extension wiring has anything to do with it.

20 metres should not be too long for an extension, but you can't discount the possibility of miswiring somewhere.
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Old 14th Mar 2017, 8:11 pm   #3
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Default Re: 746 Telephone Problem

Quote:
I wondered if the issue might lie in the extension lead simply being too long, whether there might be some limit to how long such a lead can be
A few hundred yards shouldn't be problem, how far is the box?
 
Old 15th Mar 2017, 6:27 pm   #4
YoungManGW
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Default Re: 746 Telephone Problem

Julie, I will try moving the 746 and plugging it in in the house, report back on what happens.

Merlin, it's about 60 feet from the socket to the 746 in the kiosk.

Thanks for the assistance so far. Stand by!

Regards,
Richard
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Old 21st Mar 2017, 5:17 pm   #5
YoungManGW
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Default Re: 746 Telephone Problem

My apologies for the delay - other matters took over.

Attached is a photograph of how the phone is wired up. I think this is correct:

Handset
Red T1
Green T2
Blue T3
White T10

Line
Blue T6
Red T8
Green T15
White T18

Straps
T5-T6
T16-T17-T18-T19

Rectifier 205 T1-T2
3.3k resistor T4-T5

Does this help with the diagnosis?

Many thanks,
Richard
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Old 21st Mar 2017, 8:47 pm   #6
TonyDuell
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Default Re: 746 Telephone Problem

Those connections look right. But the telephone is a 706 Mk1, not a 746. It doesn't make much difference (electrically they are much the same if the regulator is in-circuit, as it seems to be here), but you might as well work from the correct diagram.

I would start by checking the line cord for open-circuits (plug contacts to the spade terminals) and then check things like the gravity switch (hookswitch) and dial contacts. A lot of problems are bad connections after all.
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Old 22nd Mar 2017, 11:53 am   #7
giraffenigel
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Default Re: 746 Telephone Problem

Have you moved it to inside the house to test it as Julie suggested? Is that a new red line cord with a BT plug on, if not, how have you connected it to the extension?
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Old 25th Mar 2017, 6:37 pm   #8
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Default Re: 746 Telephone Problem

Just as a matter of interest, it looks from your photograph as though the spade terminal connected to T6 may well be shorting to that on T16. Regards Pete
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Old 25th Mar 2017, 10:17 pm   #9
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Default Re: 746 Telephone Problem

Is a track from top left solder joint rotted through? (on the PCB photo) are there any dry joints?


John.
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Old 26th Mar 2017, 1:43 am   #10
julie_m
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Default Re: 746 Telephone Problem

What does your 706 telephone do if you plug it into a socket in the house (via an ADSL filter, if your installation requires such things) ? Call it from your mobile. Does it ring properly? Can it answer a call? Hang up and try the other way, dialling your mobile number from the 706. Does the dial tone stop with the first pulse of the first digit being dialled? How is the sound quality?

Works perfectly in house ⇒ fault lies in extension wiring.
Same problem in house as in kiosk ⇒ fault lies in phone.
Different problem in house than in kiosk ⇒ problems with both phone and extension wiring.

If necessary, get the phone to a state where it works perfectly inside the house (refer to this wiring diagram and these conversion notes), before trying it in the kiosk again.
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