UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Telephony and Telecomms

Notices

Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

Closed Thread
 
Thread Tools
Old 14th Mar 2010, 5:32 pm   #21
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

Ok I will get back to you with adequate photos also
Chris450d is offline  
Old 15th Mar 2010, 1:24 pm   #22
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

Please click this link and refer to the first two photos shown. Please note that this is another phone and not the initial GPO 706 set that I am attempting to convert.

http://www.***********/photos/chrisellul/

I have checked with my telephone service provider and unfortunately they do not offer a pulse dialing service. This being the case, will I still be able to use the phone as a handset device only and listen/speak?

With regards to the photos: I have wired the line cord with a non-uk type cord as per:
http://www.britishtelephones.com/pstconv2.htm

As you can see, the wiring diagram differs slightly from the gpo 706 diagram. However, I have not understood what make/model this phone actually is and neither have I found a relevant convertion diagram.
With the wiring as in the picture, I get the usual beeps when I listen through the handset and it seems fine at first. However, If I place the receiver down and try to ring the phone, it appears as number busy. Also, If i leave the handset off for a while, the beeps relay an 'engaged' line and even if i click the reciever buttons this does not free up the line.

Also worth noting is that the original line cord used 3 wires and not 4.

Any help is appreciated!
Chris450d is offline  
Old 15th Mar 2010, 3:51 pm   #23
Dave Moll
Dekatron
 
Dave Moll's Avatar
 
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,118
Default Re: GPO 706 dead

Quote:
Originally Posted by Chris450d View Post
I have checked with my telephone service provider and unfortunately they do not offer a pulse dialing service. This being the case, will I still be able to use the phone as a handset device only and listen/speak?
If you are happy to be unable to dial out from this 'phone, there is no reason why everything else shouldn't be just fine.

If you wish to be able to use this, or any other, pulse-only 'phone to dial out, you could always invest in a pulse-to-tone converter. The external plug-in version is the simplest, though the internal version (of which I have one) offers greater functionality - albeit for a single 'phone.

N.B. I have no personal connection with the Rotatone other than as a satisfied customer.
__________________
Mending is better than Ending (cf Brave New World by Aldous Huxley)
Dave Moll is online now  
Old 15th Mar 2010, 4:14 pm   #24
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

Well that seems like an interesting choice! If I get this phone to work I'd consider one of those for sure...

Big thanks

Last edited by Dave Moll; 15th Mar 2010 at 4:22 pm. Reason: unnecessary quote of preceding post removed
Chris450d is offline  
Old 17th Mar 2010, 9:54 am   #25
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

Any help with the latest phone and how to wire the handset to work well?
Thanks!
Chris450d is offline  
Old 17th Mar 2010, 9:58 am   #26
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

The new phone looks like a 706/746 clone with the regulator mounted on the printed circuit board. Check it against the N806 diagram to confirm this. Don't worry about the straps and cord connections. Make sure the basic circuit is OK

Looking at your wiring the first thing I notice is that the handset cord is incorrectly connected with no wire on T3. Looking at the diagram it's difficult to see where the blue wire from the mic goes to. I would expect it to go to T3, but the diagram may show T13. Even so you have no wire on T13 either. Check your connections carefully with reference to post 18.

EDIT. Forget that the new phone uses T11 instead of T3.

Can you post us a picture of the plug end of the line cord showing the colours please.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 18th Mar 2010, 7:37 pm   #27
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

back with some more pics as requested

[img]http://farm3.static.***********/2709/4443009423_b8ca09ea7f.jpg[/img]
this is the original line cord indicating the 3 red/white/green

[img]http://farm5.static.***********/4028/4443010349_8d3c715abb.jpg[/img]
here is the non-bt to bt converter which was previously attached to the phone's pcb.

hope that clears that one out

Last edited by Chris450d; 18th Mar 2010 at 7:38 pm. Reason: big images
Chris450d is offline  
Old 18th Mar 2010, 7:59 pm   #28
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

Could you turn your plug round so that it looks like the attachment and tell us the order of the colours IN THE PLUG from top to bottom.
Attached Thumbnails
Click image for larger version

Name:	cord4_502.jpg
Views:	82
Size:	14.4 KB
ID:	33534  
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 18th Mar 2010, 8:08 pm   #29
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

black
red
green
yellow
Chris450d is offline  
Old 18th Mar 2010, 8:58 pm   #30
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

If that's correct (it's the opposite of that shown in the second link in post 22). Connect the wires as follows:-

Black to T8.
Red to T6.
Green to T15.
Yellow to T18.

Or if the colours are as per the link:-

Yellow to T8.
Green to T6.
Red to T15.
Black to T18.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 19th Mar 2010, 12:19 pm   #31
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

Somehow I only get a pulse when I connect at least the Green to T6 and Red to T18. MAybe the sort of conversion is incorrect for this sort of circuitry?

I have strapped according to the 706 conversion but perhaps this isnt the right way to do this?
Chris450d is offline  
Old 19th Mar 2010, 12:34 pm   #32
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

The phone you show in your pictures is exactly like a British Post Office 706/746 except that it uses T11 instead of T3 for one of the microphone connections. Your strapping is correct. The handest cord is connected correctly. With a correctly connected line cord the phone would work with a UK PHONE SOCKET.

I am wondering whether the phone sockets in Malta are wired differently. Either that or perhaps your sockets are not wired correctly?

If you have a test meter set it to a volts range capable of measuring in excess of 60V DC. Plug in your line cord WITHOUT the phone and measure the voltages on the various wires. You should find that two wires have 50V across them.

The positive wire or A leg should be connected to T18. The negative wire of B leg should be connected to T8. with those connections you should be able to get dial tone, answer an incoming call (though the phone won't ring), speak to the other party and the when ON HOOK the line shouldn't be busy to incoming calls.

Try that. If it doesn't work we'll need to know how Maltese phone sockets are wired.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 19th Mar 2010, 12:40 pm   #33
ppppenguin
Retired Dormant Member
 
ppppenguin's Avatar
 
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
Default Re: GPO 706 dead

If Malta uses the UK style phone connector it is possible that the wiring is different. I got caught out in Israel who use the UK connector but with the speech circuit on pins 3 & 4 and no separate bell wire. As against 2 & 5 in the UK with pin 3 as a separate bell wire.
ppppenguin is offline  
Old 19th Mar 2010, 12:48 pm   #34
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

Chris. Can you explain what you mean by a "pulse" please. Do you mean dial tone, sometimes called proceed tone?
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 19th Mar 2010, 12:56 pm   #35
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

There are four wires in the cord and three tags (T6, T8 and T18) in the phone to connect them to. I make that 24 ways of connecting the phone. That would require a lot of trial and error to get the right combination.

The meter approach is probably best.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 19th Mar 2010, 1:07 pm   #36
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

I have now changed the plug to the type shown in post #28. With this plug I removed strap 17 & 18. Connecting red to T6 and white to T18 I get the proceed tone as you described. when someone calls the phone from a different line and answer it, I can hear the calller perfectly!

However the mic and ringer have not been connected yet.

Most likely you are right about Malta connections that the wiring is moved around!

on voltmeter test, i get 51.4V across red and white and 49.5V across red and blue
Chris450d is offline  
Old 19th Mar 2010, 1:24 pm   #37
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

If I leave the strap T17 - T18 connected, and connect white to T18 and Red to T6 the ringer vibrates once whenever I lift and replace the receiver. Also, even though i Do get the proceed tone... I get the same problem as in post #22.

Really baffled :s
Chris450d is offline  
Old 19th Mar 2010, 3:17 pm   #38
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: GPO 706 dead

When you measure voltages what are the polarities? The leads of your meter will be red and black denoting + and -. If red is connected to the positive side and black to the negative side of the supply the meter will read forwards. If the leads are reversed the meter will read backwards or in the case of a digital meter be preceded by a negative sign.

The fact you have voltages on all three leads makes me wonder whether one of the connections in the socket is an earth connection.

Can you look inside your MASTER JACK and see whether there is a capacitor in there.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 21st Mar 2010, 9:46 am   #39
Chris450d
Retired Dormant Member
 
Join Date: Mar 2010
Location: Naxxar, Malta
Posts: 21
Default Re: GPO 706 dead

http://www.***********/photos/chrisellul/4450283496/

Pic of the insides of the master jack! Hope that clears things out a bit!
Chris450d is offline  
Old 21st Mar 2010, 4:37 pm   #40
Dave Moll
Dekatron
 
Dave Moll's Avatar
 
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,118
Default Re: GPO 706 dead

I notice that there are two pairs of wires connected between terminals 2 and 5. Presumably, one is the line in and the other goes to an extension - in which case you have a two-wire connection to that extension (i.e. no separate bell wire). This is only significant for instruments plugged into the extension, but would mean that anything with a standard BT-type plug using the extension would not ring unless it has its own ringing capacitor (or the extension uses a second master-type socket).

Anything correctly wired to the UK standard and plugged into the socket shown should work correctly. As far as I'm aware (though I stand to be corrected), this should be true regardless of the polarity of the incoming pair, though I would hope that red is +ve and green is -ve.
__________________
Mending is better than Ending (cf Brave New World by Aldous Huxley)
Dave Moll is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 9:29 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.