Ringer Fault Finding
BT type 746 phone
Northern Telecom 2500 DTMF phone

Phone does not ring

Is the Power supply indicator lit? Is there power to it? Unplug from ringer - if still not lit, Power supply is faulty and needs to be returned to Precision Vision. Is the status indicator lit red in stop mode? If not, check the Power supply is set for 12v Dc with the Polarity plug set for +ve centre pin and plugged into the ringer. Press the start button, does the status indicator flash green? If not, is the phone you are using known to be OK? unplug phone or bell then retry - status indicator now flashes green. Phone or its connections are faulty. Still not working? Ringer unit is faulty and needs to be returned to Precision Vision.

Phone rings but does not cancel when receiver is lifted and ringing signal can be heard in earpiece

Check wiring to 431A BT plug, make sure pins 2,5 are connected to the line in terminals on the phone e.g. the BT/GPO telephone type 746 with dial and integral bells line in terminals are T8&9 to pin 2. T16,17,18&19 to pin 5.

Phone does not ring but status indicator flashes green

Check wiring to 431A BT plug, in the example above, the phone may have been modified and the bell may not be in circuit, in addition to the above connect T4 to pin 3 of the BT plug.

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