Hello. Help please with a '706' Telephone

[Bethstevens]

Hello everyone.
I wonder if anyone can help me please?

I have been given a '706' Telephone and with the help of the internet (and a conversion kit bought online) I have managed to get it working. I can dial out and it will ring and the speaker and microphone seem to be working OK
But there is a problem which I cant seem to find help with via Google etc.

What happens is... When the handset it put down the call doesn't disconnect unless I hold down the small 'press' button (above the dial). If I hold that down and the handset is on the hook it works perfectly, but if I release the 'press' button it stays connected to the call

If the above makes sense, I would love to hear how to sort that out as I remember using this phone in my aunts house when I was small

Thanks
Beth x

[AndiiT]

Hi,
It sounds like the Auxilary button (to give it the correct term) has either been wired for timed break recall (unlikely) or the phone was originally used on a shared service/party line so the button will be disconnecting one leg of the line pair when you press it, clearing the line.

So to get to your issue, is it possible to post us a picture of the way your have done the conversion wiring as it's often easier to see from a picture if something has been overlooked or wired incorrectly which can easily be done.

In addition to this, if the phone has been wired for party line use there are often less straps available in the phone than that required for conversion, of course a bit of wire will suffice in place of a strap although I'm sure that you will have done this if required.

As I mentioned a picture of the internal wiring would be good. If you are sure everything is wired correctly though, you may have an issue with a faulty hook switch on the transmission board. Is strap T5 -T6 present?

A further thought is that the case may not be fitted correctly. Have your tried to clear the line using the switch hooks with the cover removed?, I have had a few 706's that have been very fussy about the way the cover is fitted, particularly over the hook switch operating levers.

Regards

Andrew

[Bethstevens]

Hi Andrew.
Thanks for the reply... The fault still exists without the cover fitted, holding the hook and button at the same time

I shall try and add a pic (when ive figured out how to do so)

Thanks

Beth x

Has this worked?

[AndiiT]

Hi again,
I can't see anything wrong with your conversion wiring but am struggling to see where the wires from the Auxiliary button are connected and, if they are connected they certainly aren't to the terminals that I would have expected them to be.

The marking ADPTR SS3 certainly confirms that the phone will have been used on shared service at some point and the button isn't required these days so it might be worth disconnecting the wires from the terminals that the button is connected to and see if this makes a difference.

There should be three wires from the switch associated with the button, Blue, Brown and Slate (grey) check which terminals they are connected to, before trying what i have suggested above, just in case.

Good luck

Andrew

[Bethstevens]

Hi Again.

I've disconnected all the wires from the 'press' button to the telephone and it now works as it should. However it now won't ring (It will do everything else though).

I've attached another pic of how it's now wired. Am I missing a capacitor or something?

Thanks

[Station X]

I'm afraid there was no picture attached to your post.

[Bethstevens]

Trying again...

[russell_w_b]

Your wiring looks OK on the face of it. Could you try replacing the resistor with a solid link?

Is your bell-hammer free to move and not jammed? Are your links T19 - 18 - 17 - 16 solid and contiguous?

Are you using the same telephone socket as you were when the telephone was ringing OK?

[Bethstevens]

Hi Russell

Ive heard it ringing as when the 'press' button is connected it rings fine.

I am trying it on the same socket to (the only one in the house in fact)

Thanks for everyones help up to now

Beth x

[AndiiT]

Hi, I would agree with what Russel suggests and replace the resistor across T4 - T5 with a wire link for the time being, as I mentioned previously it was difficult to see where the auxiliary switch was wired to but it may have been incorrectly wired by the previous owner in order to make the bell ring and perhaps then they gave up as they had created a transmission fault.

The resistor across T4 - T5 isn't always necessary depending on how many other phones that you have connected across the line and the distance from the exchange.

Regards

Andrew

[Bethstevens]

Fixed it!

After messing around a while I realised that the 'press' wiring was making a circuit so I tried making a link between 1 and 2 first and it worked!

Thanks for all your help everyone, ill take a pic of it in situ.

Happy bunny today here x

[Nickthedentist]

Well done!

Look forward to seeing the pic. Can't see how shorting T1 to T2 would get it to work though, as you'd be shorting-out the receiver (earpiece).

Nick.

[Bethstevens]

Actually in my excitement to tell you all that its working (well, ringing) ive not tested the handset... let me report back!

[recordamus]

You might find the following useful if you want to start from scratch:

Telephone is wired as follows. (Note: The bell coils should present a resistance of 4000 ohms. This can be achieved by inserting a 3.3K (3,300 Ohms) resistor in series with them.)
1. Remove strap T6 - T7
2. Remove strap T4 - T5
3. Insert strap T5 - T6
4. *Red wire of line cord to T8
5. *Blue wire of line cord to T6
6. Insert straps T16 - T17 - T18 - T19
7. *White wire of line cord to T18
8. *Green wire of line cord to T15
9. Insert a 3.3K resistor between T4 - T5
10. Insert a Rectifier No. 205 (if needed) between T1 and T2 (Optional)

Wire and install Bell On-Bell Off switch as follows:-
1. Remove strap T16 - T17 only. Leave T17-T18 and T19 in place with the white of the line cord.
2. Connect Brown wire of switch to T16.
3. Connect Grey and Blue wires of the switch to T17.


Kindest regards

Pete

[russell_w_b]

This might help (or not! ). No 'bell off' switch shown, but it can be seen how to connect one.

[Dave Moll]

A minor point of clarification regarding the "3K resistor if necessary", the alternative is a link between T4 and T5 rather than just leaving out the resistor.

[russell_w_b]

Indeed...

Here's a more explanatory drawing. Included are the pin connections to the PLUG, as sometimes the leads available are not the colours shown!

[Nickthedentist]

Very useful, Russell, thanks for posting.

[ThePillenwerfer]

I'll just add that "Pin 5" is the one next to the lever and 2 the furthest from it.

- Joe

[russell_w_b]

Originally Posted by ThePillenwerfer

'I'll just add that "Pin 5" is the one next to the lever...'

It is on a 'normal' plug, but the lever can go either side. RS used to sell 'left-handed' ones. Slots 1&6 were designed for 'other purposes', not necessarily telephone-related and, again, it's possible to get plugs with all six slots fully populated. I still have a few RS ones kicking around.

So... Counting the slots, L to R, with the plug uppermost, the lead towards you and the pins away from you:

1): Not used.
2): White, usually. To the common bell / speech path of your instrument.
3): Green, usually. Not used.
4): Blue, usually. Bell connection from capacitor in master LJU and 'anti-tinkle bell-shunt.
5): Red, usually. To the dial pulse path of your instrument.
6): Not used.

It is possible to get leads made up where green and blue are inadvertently reversed! So if in doubt, buzz it out.