Help needed with Bell RTT 56B

[chunya2005]

Hi,
This is my first visit to this forum, and was amazed and pleased to find a forum dedicated to vintage radios and phones, so thank you.
I picked up this Bell Belgique RTT 56B at a local auction a while back. It seems to have already been converted properly as the vendor had told the auctioneers that it had been working.
When I plug it in I can hear some very faint 'static' sound, but no dial tone, nor will it dial out or receive calls.
All the connections seem to be sound (no loose wires), and the terminals seem to be clean (but I don't know how clean they need to be) Oddly enough when I unscrewed the mouthpiece there was a piece of plastic/polythene paper between the two sections.
Hopefully someone will be able to tell me whether this lovely old phone will ever work again, but please bear in mind that I am pretty much an electronics dinosaur.
Thanks in advance

[dagskarlsen]

Looks like the conversion has been done according to this page: http://www.britishtelephones.com/bellt3.htm

These conversions are not always caring about maximum speech quality, because they are made with the ringer load as the most important, but still they do work reasonably well. Your phone should work an a BT line with a master (and slave sockets).

The handset modifications looks a little odd, disconnect the phone and put battery of 4.5-9V between the terminal A and B you should be able to speak, and hear yourselves pretty well. If OK the wire between the socket and the phone has to be tested.
If not working, remove the handset wires from the phone, and try the battery between red and black. You may try to switch red and black if the handset only works with the right polarity. You should hear yourselves very load, and it may be loud pops in the earpiece when you connect/disconnect the battery.

dsk

[chunya2005]

I should have mentioned that the phone was plugged into a BT MK3 box, which takes the phone line and Broadband. Might this be a problem?

Many thanks.

Many thanks DSK for your response, and I'll get a 9v battery and try it. It would be great to get this working again, it's two years younger than me and just the sort of phone that I grew up with.

[dagskarlsen]

I do not know BT MK3, but if another normal phone works here, I see no reason for not getting the voice and ringing to work. Rotary dials may be another issue, but that might be solved with a converter if needed.

You may lend the 9 V battery from a smoke detector

dsk

[chunya2005]

Hello dsk,
First of all apologies, for some reason I wrote 58B whereas it should have been 56B.

I found a 9v battery, followed your link and then went to the Bell (Antwerp) circuit diagrams. Unfortunately I really do struggle with comparing what appears in the diagrams to what I am seeing as shown in the photo.
Looking at the photo, and the two columns of connected wires, the first with 5 rows and the second with 4 rows, which are the A and B terminals? Do I unscrew these wires and attach them to the battery?
Many thanks

[dagskarlsen]

The B should have an internal grey (slate) wire soldered to the terminal.
A should be brown, And no You do not have to disconnect wires for this test.

For the 2.nd test you should unscrew the handset wires.

dsk

[dagskarlsen]

If you look at the bakelite, the screw terminals should have som molded letter in the bakelite It might be R MR M C on the row of 4, and A S C1 B E on the other row.

dsk

[chunya2005]

Good Morning,
Many thanks for all of your help. The first test just produced clicking when I connected the terminals, with the second (connecting Red and Black) I could hear my voice ... so all I did was to disconnect and reconnect all the wires and the phone now works perfectly, and what a lovely ring.
Again, many thanks