GPO 706 Phone not ringing - UK Vintage Radio Repair and Restoration Discussion Forum

rustmonster · 9th Jan 2014, 3:38 pm

Bought as a Christmas present, was sold as fully working, though seller mentioned that the ringer may become faulty in transit and need a "slight adjustment" when it arrived.

It can dial out fine, I have an ADSL microfilter attached, the only problem is the bell won't ring when the phone is dialled.

There's some bodged connections between T5 & 6 and also between T18 & 19, I wonder if it could be an issue with that? Also, there's a spare blue, grey and brown cables coming from the top of the phone, I wonder if they need to attach somewhere...

Any help would be greatly appreciated.

Station X · 9th Jan 2014, 4:21 pm

Is any forum member willing/able to post a good clear picture showing the connections of a correctly converted 706/746? We could make it a sticky and it would be a good place to point members, with a problem like this, to.

Nickthedentist · 9th Jan 2014, 4:48 pm

Here's a pic I found on my hard drive - lifted off the internet ages ago I would imagine. Not the clearest but it may help the OP. (The component between terminals 4 and 5 is a 3.3Kohm resistor, but if you haven't got one to hand, for testing purposes, the terminals should be linked.

Good luck,
Nick.

Station X · 9th Jan 2014, 4:59 pm

rustmonster. It looks like your phone isn't wired correctly. Follow the instructions on this page (scroll about halfway down):-

http://www.britishtelephones.com/pstconv1.htm

Info summarised.

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 (object with coloured stripes on it).
10.Insert a Rectifier No. 205 (if needed) between T1 and T2.

You can leave out the rectifier 205 and substitute a strap for the 3.3K resistor for testing purposes.

rustmonster · 9th Jan 2014, 5:45 pm

Thanks so much guys, got it working.

It seems the Rectifier 205 is not needed and I'll look at replacing the strap with a 3.3k resistor.

In the meantine should I remove the strap at T4 - T5 while I get a resistor or is it safe to leave in there in the short term?

Nickthedentist · 9th Jan 2014, 5:58 pm

Leave it in or you'll get no ringing. Replacing it with a resistor just reduces the current drawn a bit, so its REN is lowered to about 1, meaning that any other phones you've got connected will still ring.

Nick

nutteronthebus · 9th Jan 2014, 8:49 pm

Hi the spare blue, grey and brown cables coming from the top of the phone, are a recall switch for PABX (private automatic branch exchange) and are not needed on a home phone just insulate them and tie them back out of the way

russell_w_b · 9th Jan 2014, 9:37 pm

Quote:

Originally Posted by nutteronthebus

just insulate them and tie them back out of the way

I connected mine across the mic terminals to short it out and so make a 'mute / secrecy' button.

nutteronthebus · 10th Jan 2014, 9:04 am

For full information try this site

http://www.britishtelephones.com/t706.htm

9th Jan 2014, 3:38 pm	#1
rustmonster Retired Dormant Member Join Date: Jan 2014 Location: London Posts: 2	GPO 706 Phone not ringing Bought as a Christmas present, was sold as fully working, though seller mentioned that the ringer may become faulty in transit and need a "slight adjustment" when it arrived. It can dial out fine, I have an ADSL microfilter attached, the only problem is the bell won't ring when the phone is dialled. There's some bodged connections between T5 & 6 and also between T18 & 19, I wonder if it could be an issue with that? Also, there's a spare blue, grey and brown cables coming from the top of the phone, I wonder if they need to attach somewhere... Any help would be greatly appreciated. Attached Thumbnails

9th Jan 2014, 4:21 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: GPO 706 Phone not ringing Is any forum member willing/able to post a good clear picture showing the connections of a correctly converted 706/746? We could make it a sticky and it would be a good place to point members, with a problem like this, to. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

9th Jan 2014, 4:48 pm	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: GPO 706 Phone not ringing Here's a pic I found on my hard drive - lifted off the internet ages ago I would imagine. Not the clearest but it may help the OP. (The component between terminals 4 and 5 is a 3.3Kohm resistor, but if you haven't got one to hand, for testing purposes, the terminals should be linked. Good luck, Nick. Attached Thumbnails

9th Jan 2014, 4:59 pm	#4
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: GPO 706 Phone not ringing rustmonster. It looks like your phone isn't wired correctly. Follow the instructions on this page (scroll about halfway down):- http://www.britishtelephones.com/pstconv1.htm Info summarised. 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 (object with coloured stripes on it). 10.Insert a Rectifier No. 205 (if needed) between T1 and T2. You can leave out the rectifier 205 and substitute a strap for the 3.3K resistor for testing purposes. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

9th Jan 2014, 5:45 pm	#5
rustmonster Retired Dormant Member Join Date: Jan 2014 Location: London Posts: 2	Re: GPO 706 Phone not ringing Thanks so much guys, got it working. It seems the Rectifier 205 is not needed and I'll look at replacing the strap with a 3.3k resistor. In the meantine should I remove the strap at T4 - T5 while I get a resistor or is it safe to leave in there in the short term?

9th Jan 2014, 5:58 pm	#6
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,865	Re: GPO 706 Phone not ringing Leave it in or you'll get no ringing. Replacing it with a resistor just reduces the current drawn a bit, so its REN is lowered to about 1, meaning that any other phones you've got connected will still ring. Nick

9th Jan 2014, 8:49 pm	#7
nutteronthebus Hexode Join Date: Jun 2011 Location: Glossop, Derbyshire, UK. Posts: 487	Re: GPO 706 Phone not ringing Hi the spare blue, grey and brown cables coming from the top of the phone, are a recall switch for PABX (private automatic branch exchange) and are not needed on a home phone just insulate them and tie them back out of the way __________________ Any tool can be used as a hammer but a screwdriver makes the best chisel

10th Jan 2014, 9:04 am	#9
nutteronthebus Hexode Join Date: Jun 2011 Location: Glossop, Derbyshire, UK. Posts: 487	Re: GPO 706 Phone not ringing For full information try this site http://www.britishtelephones.com/t706.htm __________________ Any tool can be used as a hammer but a screwdriver makes the best chisel