Gpo746l telephone ringing issues in spain

[dsk]

UK uses 25 Hz, that causes the hammer to hit each gong e.g. 25 times each second, and that is what it is made to do.  When you double the frequency, the hammer tries to move at the double speed, and that may not be so easy. This will also have influence on the current and balance between capacitors and coils etc. but should hopefully not be a great issue here.

What may we do to help the ringer to work at double speed?  The ringer yoke could be adjusted to travel a shorter distance. This may make it vibrate, better, but it will not hit the gongs, so we just adjust the gongs closer. They are usually eccentric, so they could be turned to right position. (The right position is where you believe the sound is the best)  This information is based on experience with Norwegian telephones used on an Ericsson PABX with 50 Hz ringing. (but only 48V) (Erifox)

dsk

[G-Man]

These links to Bob's site may be of assistance with your instrument.

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

How to wire your Telephone No. 706 to make it work on Plug and Socket-

   
• http://www.britishtelephones.com/pstconv1.htm#700

[twocvbloke]

The standard ringer mechanism in a 700 type phone has no biasing, it's just a universal straight-line ringer, so should ring at most frequencies, the main adjustment needed would possibly to rotate the gongs inwards a little to compensate for the faster rate, I played about with my Linksys PAP2T and it's adjustable frequency settings and my GPO phones always seemed to ring at whatever rate they were fed...

The voltage shouldn't be to much of an issue though as long as it's over 40v...

I have made an error this is not a 746 this is an gpo706L im so sorry for my stupid mistake.

The 706 and 746 wiring is virtually identical, the only difference between them is the brown dial wire was moved during the 706 production, after that modification, the two circuits were pretty much identical...

[G-Man]

Here is the wiring diagram courtesy of Sam's website:

   
• http://www.samhallas.co.uk/repository/n_diagrams/0000/N806.pdf

[dsk]

http://tinyurl.com/qzkxj8e

Is actually the ringing frequency 50 Hz in Spain?  I know the regular electric frequency is 50 Hz.

dsk

[Applemac]

I have followed the samhallas wiring and tried them the phone still does not ring....  The ringer does not even viberate Its as though no signal going through to the ringer.

[dsk]

OK, then we take it slow from the beginning. Could you please tell us if you have any electric meters to read voltage (DC) millimps, ohms etc? Does the phone work when you try to call others? (just not ringing)? Could you please post some pictures of the inside of the phone with wires and links as it is now?

dsk

[G-Man]

See if this helps to simplify the schematic. You said there are now only two line wires since it has been converted to an RJ11 plug. The red and green may have been transposed in the drawing, but that should not affect the sets operation. 

Make sure that all of the jumpers are in place for the bell and capacitor. 

I believe the British call for a resistor to be inserted in series with the bell, but as an expedient in case you do not have one close at hand, use a wire jumper to see if you can detect movement of the bell's armature.

[Jack Ryan]

G-Man, I believe the phone was already "converted" - it needs to be "un-converted" for operation in Spain.

Following the instructions Dsk, G-Man, I and others have given should work. The DC blocking capacitor (C1A) must be still present if original (it's a double). Its presence in the circuit is required.

Applemac originally said that the ringing frequency in Spain was 50Hz - can this be verified? 50Hz might be too high for the bell without adjustment but at the moment it is not even vibrating so it might not be connected at all.

Is the circuit as per G-Man's post?
http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=15124.0;attach=131220;image

I would jumper T17 to T18 with wire rather than the resistor and then carefully double check all the connections.

Is it possible to connect A and B (the telephone connections) to the telephone line directly. I'm sure the adaptor works but you need to have the correct wires connected and it is just another potential issue to contend with.

I can't remember if you (Applemac) said but has the (converted) phone ever worked? Did it work in the UK  before taking it to Spain?

Jack

[G-Man]

Hi Jack-

I was hoping to make the schematic a bit more understandable for Applemac but will willingly defer to your much superior knowledge than what myself and most other possess, regarding GPO/BPO and European telephones in general.

For years I have held-off "dissing" the BPO's bell wiring schemes, but it does seem that they made it much more complicated than what was necessary, simply to save a few pennies of the cost of additional capacitors for auxiliary ringers.

The added cost of training "inspectors," more wires, prone to additional faults, etc., in the long run, seems to have negated any potential savings.

Just my two-pence worth.

[Applemac]

Here are some pictures of the inside, remember im in spain.

[dsk]

At the encl picture.
A Remove this resistor and put in a wire D.
B remove this metal strap so we break the connection C between T5 and T6
D put inn a connection here, it may be the one you removed from T5-T6 or a wire.
Be sure the connection to your line is the red R and White T wires.  (you should get dial tone)
Be sure to not connect any other wires to the telephone network. (You may remove blue wire, and just tape it)



dsk

[Applemac]

Dsk have done what you describe in the pic, I get a tone when picking up the phone, can dial out, yet on recieving a call still no ringing.

[dsk]

Any sounds at all, hum or buzz or something when it should ring?
dsk

[Applemac]

Dsk, no sound no viberation at all.