BT 746 - rotary dial does not retract and no dial tone
 

Hello all,
Recently bought an old 746 phone, and did the conversion for a modern line. However, there is no dial tone, and the rotary dial does not retract. Can anyone help me, or know of any specialists in Birmingham?
Thanks

Re: BT 746 - rotary dial does not retract and no dial tone
 

If you "retract" the dial manually do you get dial tone then?

Re: BT 746 - rotary dial does not retract and no dial tone
 

Is it that you get no dial tone even with the dial in its rest position, or is the dial unable to return to this position? If the latter, this would explain the absence of dial tone as the transmitter and receiver are both shorted out while the dial is "off-normal" (i.e. away from its rest position).

Regarding the dial not returning, it would be worth opening up the 'phone and checking that there is nothing obstructing the dial mechanism (which may be enclosed in a plastic "cup" behind the dial).

Re: BT 746 - rotary dial does not retract and no dial tone
 

The rotary dial has 5 wires, when the dial is moved out of the rest position 2 of these short out the receiver (loudspeaker) to eliminate noise. 2 of the 3 others shorts out the transmitter (microphone) to protect it from damage, The third is connected to the 2 others until the dial returns, when it returns it sends out small breakes (pulses) on the line to tell the exchange what number it dials, these pulses must be of a pretty accurate timing to work OK. A 0 gives 10 breakes of approx 67 milliseconds with approx 33 milliseconds between during a time of 1 second. when a 5 is only 5 of those pulses etc.

When the dial is in rest position you should have the dial tone.

Re: BT 746 - rotary dial does not retract and no dial tone
 

A non retracting dial is often caused by a broken spring.