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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

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Old 2nd Jan 2017, 10:22 pm   #1
els1967
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Default 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?
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Old 2nd Jan 2017, 10:32 pm   #2
TonyDuell
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Default 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).
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Old 2nd Jan 2017, 11:22 pm   #3
els1967
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Default 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.
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Old 3rd Jan 2017, 10:53 pm   #4
JohnBHanson
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Default Re: GPO Bellset 44

Have you replaced the carbon transmitters in the phones with electronic ones - if so these need more voltage to operate.
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Old 5th Jan 2017, 10:55 am   #5
els1967
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Default 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...
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Old 5th Jan 2017, 11:04 am   #6
els1967
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Default 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?
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Old 5th Jan 2017, 12:55 pm   #7
TonyDuell
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Default 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.
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Old 5th Jan 2017, 1:01 pm   #8
els1967
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Default 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.
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Old 5th Jan 2017, 1:10 pm   #9
TonyDuell
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Default 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.
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Old 5th Jan 2017, 6:16 pm   #10
Pellseinydd
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Default Re: GPO Bellset 44

Quote:
Originally Posted by TonyDuell View Post
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.
A 'Press Button G' was a round dark brown Bakelite surface mounted push button with a round white button in the middle - very like an old fashioned bell push. Just like the one on eBay in item number 371817091073

They had a single make contact.

Ian J
CNet 0352 2345
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