Late 60's 746 - UK Vintage Radio Repair and Restoration Discussion Forum

oldticktock · 1st Mar 2011, 9:42 pm

Hi
Never set foot in the section of the forum before, so here goes.

My workshop phone works fine but a number of people have stated that I sound a little on the quiet side, If I move my mouth close (1 inch from mouth piece) to the mouth piece they say it's fine now.

Is there anything that may be degrading the amplification of voice, any hints tips to look at. I've done nothing to this phone at all it rings fine, dials out fine other than this little issue it ok.

Thanks
Chris

Tim · 1st Mar 2011, 9:56 pm

Hi Chris
That's a 706 unless my eyes deceive me............
Sound problem could be mic(might be old type with centre contact on this one) or the regulator board

oldticktock · 1st Mar 2011, 10:00 pm

Hehe see what do I know, I only know what end to speak into

Darren-UK · 1st Mar 2011, 10:00 pm

Yes, it looks like a later 706 to me too.

On the problem, much depends on how soft your own voice is and how you hold the handset. I've seen people hold them with the mic well below, even beneath, their chins. Otherwise I'd suspect as per Tim's post above.

oldticktock · 1st Mar 2011, 10:04 pm

Hi Darren I think you probably hit the mark. I did wonder if it was me and I do tend to have it at chin level I'm so used to using modern phones and tend to forget. When the other end says I'm a bit quiet I move it up and they say that's better. The wife often has the same issue with it so I guess we better correct our poor habit.

DOH I may know what end to speak into but not correctly......... user error

Soz to waste your time guys

Chris

Edit : any ideas on the age? the chap who sold it to me said it was installed in his house in 1968 and was only removed last year, Is this correct or spin? The centre piece I put in as It was empty of the number cover. I made a little label from one I had seen on the web, cut out a piece of plastic then made a retaining clip to keep it all there.

And how can you tell a 706 from a 746

AndiiT · 1st Mar 2011, 10:32 pm

Hi,
For the quiet voice problem it may be worth modifying the transmitter insert to the updated electronic type 21 transmitter, which is a direct replacement for the older carbon granule type.

Regarding the age of your telephone, somewhere on the base there should be a stamp bearing the number 706 which will have three letters after it indicating the manufacturer, then a further two digits - these digits indicate the year of manufacture i.e 706 GNA 77 would indicate 1977, where GNA is the manufacturers identification code.

If there is a yellow sticker on the telephone, perhaps covering the original legend, this indicates that the phone has been through BTs "wipe up process at one of their refurbishment centres.

More information about these markings can be found here and here

The cases of the 706 and 746 differ, the 746 being the later of the two models, take a look at 706 and 746

Regards
Andrew

AlanBeckett · 1st Mar 2011, 10:36 pm

Quote:

Originally Posted by Darren-UK

.... and how you hold the handset. I've seen people hold them with the mic well below, even beneath, their chins.

A friend of mine does just that. He gradually fades out, then I say 'Pete, speak into the Mic' at which stage he 're-appears'.
Alan

oldticktock · 1st Mar 2011, 10:39 pm

Thanks Andrew,for the info and links,maybe mine is a dodgy one as there is nothing on the base whatsoever. Maybe I should have a peek inside.... so I did.

Chris

AndiiT · 1st Mar 2011, 11:05 pm

Hi,
This is a 706 style telephone but isn't actually a 706! It is more likely an Ericsson N1900 which was used by the GPO as their 706 model.

As this telephone also has no regulator fitted it may have originally been used on a PAX where line lengths would be relatively short; If you live some distance from the exchange, this may explain why you have the faint speech problem when using this phone.

It may be difficult to date exactly unless you can find any clues stamped anywhere on internal components.

I have also noticed that it has been converted for "two-wire" working which although not a major issue may cause the phone bell to tinkle during dialling when using any other pulse dialling phones connected to the same line.

Regards
Andrew

oldticktock · 1st Mar 2011, 11:14 pm

Cheers Andrew, you have been most helpful, at least I know it's origins and that the story of it's installation was perhaps just that, a story.

I'm about 5 miles from the exchange so not sure if that constitutes close or far in telephony terms, but certainly greater than this phone was perhaps intended for. I shall just have to remember to hold it a bit closer and all will be well.

Thanks for everyone's input.

Chris

AndiiT · 2nd Mar 2011, 8:44 pm

Hi,
Looking at your photos again, I see that there is a 150 Ohm resistor fitted between T1 and T10, this may be there to offer a degree of side-tone in absence of the regulator and anti-side-tone network.
It might be worth experimenting with the value of this resistor to see if that makes a difference to the weak speech issue, 5 miles from the exchange probably would have some bearing on speech quality with no regulator fitted but I don't think that it is at the exchange limits.

Also try fitting a strap to T5 - T6

Andrew

JCM3000 · 5th Mar 2011, 12:50 pm

It looks like the AEP logo in scuffed white paint on the base - would explain the non-standard internals.

1st Mar 2011, 9:42 pm	#1
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Late 60's 746 Hi Never set foot in the section of the forum before, so here goes. My workshop phone works fine but a number of people have stated that I sound a little on the quiet side, If I move my mouth close (1 inch from mouth piece) to the mouth piece they say it's fine now. Is there anything that may be degrading the amplification of voice, any hints tips to look at. I've done nothing to this phone at all it rings fine, dials out fine other than this little issue it ok. Thanks Chris Attached Thumbnails

1st Mar 2011, 9:56 pm	#2
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: Late 60's 746 Hi Chris That's a 706 unless my eyes deceive me............ Sound problem could be mic(might be old type with centre contact on this one) or the regulator board __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

1st Mar 2011, 10:00 pm	#3
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Late 60's 746 Hehe see what do I know, I only know what end to speak into

1st Mar 2011, 10:00 pm	#4
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Late 60's 746 Yes, it looks like a later 706 to me too. On the problem, much depends on how soft your own voice is and how you hold the handset. I've seen people hold them with the mic well below, even beneath, their chins. Otherwise I'd suspect as per Tim's post above.

1st Mar 2011, 10:04 pm	#5
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Late 60's 746 Hi Darren I think you probably hit the mark. I did wonder if it was me and I do tend to have it at chin level I'm so used to using modern phones and tend to forget. When the other end says I'm a bit quiet I move it up and they say that's better. The wife often has the same issue with it so I guess we better correct our poor habit. DOH I may know what end to speak into but not correctly......... user error Soz to waste your time guys Chris Edit : any ideas on the age? the chap who sold it to me said it was installed in his house in 1968 and was only removed last year, Is this correct or spin? The centre piece I put in as It was empty of the number cover. I made a little label from one I had seen on the web, cut out a piece of plastic then made a retaining clip to keep it all there. And how can you tell a 706 from a 746 Last edited by oldticktock; 1st Mar 2011 at 10:27 pm.

1st Mar 2011, 10:32 pm	#6
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Late 60's 746 Hi, For the quiet voice problem it may be worth modifying the transmitter insert to the updated electronic type 21 transmitter, which is a direct replacement for the older carbon granule type. Regarding the age of your telephone, somewhere on the base there should be a stamp bearing the number 706 which will have three letters after it indicating the manufacturer, then a further two digits - these digits indicate the year of manufacture i.e 706 GNA 77 would indicate 1977, where GNA is the manufacturers identification code. If there is a yellow sticker on the telephone, perhaps covering the original legend, this indicates that the phone has been through BTs "wipe up process at one of their refurbishment centres. More information about these markings can be found here and here The cases of the 706 and 746 differ, the 746 being the later of the two models, take a look at 706 and 746 Regards Andrew Last edited by AndiiT; 1st Mar 2011 at 10:35 pm. Reason: information about phone differences added

1st Mar 2011, 10:39 pm	#8
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Late 60's 746 Thanks Andrew,for the info and links,maybe mine is a dodgy one as there is nothing on the base whatsoever. Maybe I should have a peek inside.... so I did. Chris Attached Thumbnails Last edited by oldticktock; 1st Mar 2011 at 10:52 pm.

1st Mar 2011, 11:05 pm	#9
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Late 60's 746 Hi, This is a 706 style telephone but isn't actually a 706! It is more likely an Ericsson N1900 which was used by the GPO as their 706 model. As this telephone also has no regulator fitted it may have originally been used on a PAX where line lengths would be relatively short; If you live some distance from the exchange, this may explain why you have the faint speech problem when using this phone. It may be difficult to date exactly unless you can find any clues stamped anywhere on internal components. I have also noticed that it has been converted for "two-wire" working which although not a major issue may cause the phone bell to tinkle during dialling when using any other pulse dialling phones connected to the same line. Regards Andrew Last edited by AndiiT; 1st Mar 2011 at 11:07 pm. Reason: note about two wire working

1st Mar 2011, 11:14 pm	#10
oldticktock Retired Dormant Member Join Date: Nov 2009 Location: Weardale, UK. Posts: 1,981	Re: Late 60's 746 Cheers Andrew, you have been most helpful, at least I know it's origins and that the story of it's installation was perhaps just that, a story. I'm about 5 miles from the exchange so not sure if that constitutes close or far in telephony terms, but certainly greater than this phone was perhaps intended for. I shall just have to remember to hold it a bit closer and all will be well. Thanks for everyone's input. Chris

2nd Mar 2011, 8:44 pm	#11
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Late 60's 746 Hi, Looking at your photos again, I see that there is a 150 Ohm resistor fitted between T1 and T10, this may be there to offer a degree of side-tone in absence of the regulator and anti-side-tone network. It might be worth experimenting with the value of this resistor to see if that makes a difference to the weak speech issue, 5 miles from the exchange probably would have some bearing on speech quality with no regulator fitted but I don't think that it is at the exchange limits. Also try fitting a strap to T5 - T6 Andrew Last edited by AndiiT; 2nd Mar 2011 at 8:46 pm. Reason: added information about strapping

5th Mar 2011, 12:50 pm	#12
JCM3000 Retired Dormant Member Join Date: Apr 2010 Location: Isle of Purbeck, Dorset, UK. Posts: 29	Re: Late 60's 746 It looks like the AEP logo in scuffed white paint on the base - would explain the non-standard internals.