|
Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
|
Thread Tools |
2nd Jan 2017, 10:22 pm | #1 |
Pentode
Join Date: Aug 2016
Location: Dunstable, Bedfordshire, UK.
Posts: 139
|
GPO Bellset 44
I recently purchased via Ebay a Bellset 44 complete with the phone and have been slowly restoring/experimenting with it. I'm pretty happy that I've got it all working the way that it should but there is just one thing I don't quite get. The N diagram N4308 shows a battery connected between BT10 and BT11 which powers the phones when talking from the bellset phone and the extn. with the phone line disconnected. So I've got this working with a couple of batts. and an unconverted GPO 330 and it certainly works but it's so quiet you have to talk with a reasonable volume to make yourself heard. If I call the extn. phone from "outside" it's as clear as a bell. The documentation suggest two 1.5v batteries would suffice and this is what I have connected but would it really have been this quiet back in the day?
|
2nd Jan 2017, 10:32 pm | #2 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,191
|
Re: GPO Bellset 44
I was surprised it's just 2 or 3 cells that are needed but the N-diagram confirms it. The later Planset (see diagram N625) using 700 series telephones used 10-12V.
Have you checked the battery voltage on-load just in case the internal resistance of the battery is causing an excessive voltage drop? What cells are you using (FWIW a Planset will run happily off 8 alkaline D cells). Have you tried 3 cells to see if it helps? Is it quiet speaking from main to extension and from extension to main? If it's only quiet in one direction that would suggest a problem with a particular transmitter and receiver. If both ways that possibly switching-related? I assume the transmitters in the telephones are still the original carbon microphones and that somebody hasn't fitted the innards of a Transmitter 21A (the electronic one). |
2nd Jan 2017, 11:22 pm | #3 |
Pentode
Join Date: Aug 2016
Location: Dunstable, Bedfordshire, UK.
Posts: 139
|
Re: GPO Bellset 44
Hi Tony, thanks for the quick reply. I'll take a look at the battery voltage on line when I next get a chance, that's a good idea. I'm using a couple of cheapo D cells. I'll try adding another cell, dunno why I didn't think of that Doh!
It's quite in both directions so I don't think it's switching related. All the kit is original. |
3rd Jan 2017, 10:53 pm | #4 |
Heptode
Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 661
|
Re: GPO Bellset 44
Have you replaced the carbon transmitters in the phones with electronic ones - if so these need more voltage to operate.
|
5th Jan 2017, 10:55 am | #5 |
Pentode
Join Date: Aug 2016
Location: Dunstable, Bedfordshire, UK.
Posts: 139
|
Re: GPO Bellset 44
Hi John, it's all the original kit.
By way of an update, I bought a battery holder box from Maplins and fitted 4 1.5v C batteries and now all seems to be better than it was, although still a bit quieter than a regular phone line. But that will do me. Would still be interested to know if that was generally accepted as OK quality back in the day... |
5th Jan 2017, 11:04 am | #6 |
Pentode
Join Date: Aug 2016
Location: Dunstable, Bedfordshire, UK.
Posts: 139
|
Re: GPO Bellset 44
Just one other thing. On the N Diagram page 4
http://www.samhallas.co.uk/repositor...4000/N4310.pdf it shows a 232 connected to the bellset. I've never seen a 232 with a plunger key so I was wondering what the mystery "Press button G" comment between the two phones refers to. I presume it was a plunger used to activate the buzzer in the bellset from the extn. but what sort is it? Did it fit onto the connector block some how? |
5th Jan 2017, 12:55 pm | #7 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,191
|
Re: GPO Bellset 44
As I understand diagram N4310, the internal extension telephone was either a Telephone 328 (desk) or Telephone 321 (wall mounting). These telephones had holes for buttons ('keys'). And yes, the button did sound the buzzer in the bellset.
|
5th Jan 2017, 1:01 pm | #8 |
Pentode
Join Date: Aug 2016
Location: Dunstable, Bedfordshire, UK.
Posts: 139
|
Re: GPO Bellset 44
Hi Tony, that was my understanding too but the diagram shows a 323 with bell set 26 on page 4, so it's all a bit odd.
|
5th Jan 2017, 1:10 pm | #9 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,191
|
Re: GPO Bellset 44
I think 'Press Button G' is something like a bell push. It was mounted separately if you wanted to use said telephone. I can't find much about it though.
|
5th Jan 2017, 6:16 pm | #10 | |
Heptode
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
|
Re: GPO Bellset 44
Quote:
They had a single make contact. Ian J CNet 0352 2345 |
|