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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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16th Aug 2020, 1:04 pm | #1 |
Diode
Join Date: Aug 2020
Location: Taunton, Somerset, UK.
Posts: 5
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GPO 746 Not Ringing.
Hi everyone, wondering if someone can help me.
I have read a few different threads on here about my issue but none seem to have helped so far. I have inherited a GPO746 and converted it with a Britphone conversion kit following their standard wiring instructions. The phone makes incoming and outgoing calls but the bells do not ring. They are on 2000ohm drivers (4000ohms total) and the mechanism is clear of debris etc. I have a bt cable wired white, green, blue and red from left to right. I have switched the red and white (T8 and T18) not bell. I have removed the resistor, no change I have wired the blue line cable straight to T5 with a resistot and without but no change. I am at a bit of a loss... Anything you can do to help so of be appreciated. I am UK based. One phone line in house (this one) and it does have a BT ADSL filter plugged in for the WiFi. (Not bell doesn't work in either ADSL or direct to wall) |
16th Aug 2020, 2:07 pm | #2 |
Pentode
Join Date: Jan 2019
Location: Manchester, UK.
Posts: 163
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Re: GPO 746 Not Ringing.
The resistor will be intended to be used with lower impedance bell coils and can be shorted out (not just removed) for your 4000Ω ones (REN 1 working). Best to test plugged in at the master socket (where the line comes in) to eliminate any issues with internal wiring.
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16th Aug 2020, 4:00 pm | #3 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,213
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Re: GPO 746 Not Ringing.
If you have a multimeter, measure the resistance between the 2 wires going to the bell mechanism (with the telephone unplugged from the socket). It should be 4k ohms.
Disconnect the blue wire of the line cord from T6 and insulate the end (or park it on one of the spare terminals in the bottom row like T15). Leave all other wiring as it is, but also connect T6 to T7. This will use the ringing capacitor in the telephone. If it rings then, the problem is most likely in the sockets/wiring. |
16th Aug 2020, 6:51 pm | #4 |
Diode
Join Date: Aug 2020
Location: Taunton, Somerset, UK.
Posts: 5
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Re: GPO 746 Not Ringing.
Thanks Tony,
No multimeter sadly and no joy doing as you suggest... ☹️ |
16th Aug 2020, 6:52 pm | #5 | |
Diode
Join Date: Aug 2020
Location: Taunton, Somerset, UK.
Posts: 5
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Re: GPO 746 Not Ringing.
Quote:
Modern phone works in both ADSL and wall socket 746 no bell on either ADSL or main wall socket |
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17th Aug 2020, 7:37 am | #6 |
Heptode
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 643
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Re: GPO 746 Not Ringing.
Could you please do test, moving the red wire (and only that one) coming from the ringer to Ø4 to Ø7. This will be a non converted setup, but as long as you do only have this phone on the line it should not make any problems. If that makes it ring we know that the ringer is OK, then we may test more to find out where the fault may be. (look at the arrow on the pic)
dsk |
17th Aug 2020, 6:34 pm | #7 |
Diode
Join Date: Aug 2020
Location: Taunton, Somerset, UK.
Posts: 5
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Re: GPO 746 Not Ringing.
Thanks dsk,
Tried this and no change. Just had a quick look in the incoming socket and looks like only 2 line wires are coming in instead of 4 so this might be the issue... (See pic) |
17th Aug 2020, 8:46 pm | #8 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
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Re: GPO 746 Not Ringing.
If you have two line wires coming in and you have connected the telephone with T8 - T9 linked, T4-T5-T6-T7 linked and T16-T17-T18-T19 linked with the white wire to T16-19 and the red wire to T8-9, then you have connected the telephone the 'traditional' way with the internal capacitor in circuit.
If it didn't ring like this (Post 3) then the problem is with the telephone. You could really do with acquiring a multimeter from somewhere, or someone.
__________________
Regds, Russell W. B. G4YLI. |
17th Aug 2020, 9:44 pm | #9 |
Heptode
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 643
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Re: GPO 746 Not Ringing.
What do I see in the ring?
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17th Aug 2020, 9:47 pm | #10 |
Octode
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
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Re: GPO 746 Not Ringing.
The plug in the picture in post 7 looks like it's on a micro filter. That only having two connexions is normal. There's a capacitor in the filter which connects to the socket that the 'phone plugs into.
If you've tried removing the resistor and replacing it with a strap it's looking like the bell motor is faulty. |
17th Aug 2020, 9:54 pm | #11 |
Diode
Join Date: Aug 2020
Location: Taunton, Somerset, UK.
Posts: 5
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Re: GPO 746 Not Ringing.
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18th Aug 2020, 1:30 am | #12 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,723
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Re: GPO 746 Not Ringing.
It looks like your microfilter to me too.
__________________
-- Graham. G3ZVT |
18th Aug 2020, 9:40 am | #13 |
Pentode
Join Date: Jan 2019
Location: Manchester, UK.
Posts: 163
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Re: GPO 746 Not Ringing.
If your master Openreach socket looks anything like the one in the image then you can remove the bottom plate and plug your 746 telephone into the socket on the back plate, this should remove any other wiring or other kit within the property. If the phone does not ring then it is an issue with that, other posts advise on how to proceed.
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