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Old 16th Aug 2007, 8:09 pm   #1
dpark516
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Default 706 - Can't dial out or speak

A friend recently gave me a 706, someone had had a go at converting it unsuccesfully. Having re-wired it up etc as described on this website, the phone rings and answers, the person on the other phone can be heard but i can't speak to them. Also i can't dial out. Anyone any ideas?

I've attached a picture in case anyone can see any glaring faults

Thanks
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Old 16th Aug 2007, 8:51 pm   #2
Nickthedentist
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Default Re: 706 - Can't dial out or speak

Hello!

One obvious error is that the blue and the red wires from the line cord are the wrong way round! Blue should go to T6, red to T8, and the strap between T8 and T9 can be removed.

If that doesn't solve it...

Not being able to be heard suggests that either the microphone is faulty, or that there is a short-circuit across it. Have you got another mic you can try? If you have a meter, set it to the Ohms range and stick it between T3 and T10... if you read a short-circuit, then look at the dial contacts which might be sticking closed for some reason.

Presumably there's a switch fitted to your phone? If so, how have you wired it?

The dial's contacts could also be to blame. Do they look like they've been messed with? Have you got another dial which you could try instead?

Good luck,
Nick.

Last edited by Nickthedentist; 16th Aug 2007 at 9:00 pm.
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Old 16th Aug 2007, 10:55 pm   #3
AndiiT
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Default Re: 706 - Can't dial out or speak

Hi,
The circuit for a 706 phone can be found here http://www.samhallas.co.uk/repositor.../0000/N806.pdf and wiring for the "new" plug and socket system here http://www.britishtelephones.com/pstconv1.htm#700

As nick mentions it looks like your phone is fitted with an "auxilary" button, you have two options here, either wire it for Timed break or earth recall as indicated in one of the early 706 diagrams or just park the wires from the switch on one or two of the spare terminals (T13 T14 or T15 from memory)

The outgoing speech problem could be nothing more than the fact that the red and blue wires are crossed over, as Nick has already mentioned, which would cause the ringing capacitor in the master socket and the loading of the bell coils within the telephone instrument itself to affect the speech path.

Regards
Andrew
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Old 17th Aug 2007, 2:50 pm   #4
dpark516
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Default Re: 706 - Can't dial out or speak

Hi

Thanks for your quick replies

I wired the phone as described, with the red and blue wires now in their correct places i now don't have a dial tone and when the phone rings you cannot answer it and it keeps ringing in the earpiece.

I've also parked the switch on the spare terminals, so it is now out of the system. I've checked the resistance of T3 to T10 and it is O/C and viariable across the range of the dial.

Any ideas about what can be wrong?

Thanks for your help

Des
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Old 17th Aug 2007, 6:20 pm   #5
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Default Re: 706 - Can't dial out or speak

It looks like you have an open circuit Transmitter (microphone), or a disconnection in the handset cord. Short T3 to T10 and check that with the handset off hook you can hear dial tone. If so remove the short and short circuit the transmitter instead. If you still hear dial tone the transmitter is faulty. If you don't hear dial tone the handset cord is open circuit.
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Old 17th Aug 2007, 7:26 pm   #6
AndiiT
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Default Re: 706 - Can't dial out or speak

Probably some helpful information here too http://www.britishtelephones.com/fault1.htm

Andrew
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