# PMG telecoms bell, get it working? **URL:** \ **Category:** Uncategorized\ **Created:** [15 July 2023 06:41 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582 "2023-07-15T06:41:27Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Jason252557](https://avatars.discourse-cdn.com/v4/letter/j/97f17d/32.png) [@Jason252557](https://forum.core-electronics.com.au/u/Jason252557)\ **Post date:** [15 July 2023 06:41 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582/1 "2023-07-15T06:41:27Z")
Hi, this is my first post, I have an old PMG telecoms bell and I’m wondering if I could get it going again with a small battery and an off the shelf doorbell button or am I kidding myself? 😂 > **[New video by Jason McBride](https://photos.app.goo.gl/AhF1ia5UDhaetkhq8)** ![IMG_6957](https://canada1.discourse-cdn.com/flex028/uploads/core_electronics/original/2X/7/79362782f804632c566b37f197b17e3e359ac28c.jpeg) ---
**Author:** ![Robert93820](https://avatars.discourse-cdn.com/v4/letter/r/ac91a4/32.png) [@Robert93820](https://forum.core-electronics.com.au/u/Robert93820)\ **Post date:** [15 July 2023 07:18 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582/2 "2023-07-15T07:18:13Z")
Hi Jason Welcome > [@Jason252557](#): > > a small battery I think the exchange batteries were something like 50V and would take up a complete floor of the exchange building with lots of very large 2V cells. I think from memory the bell arrangement was driven directly by the ring tone which I seem to remember being well north of 100VAC at about 17Hz. could give you quite a bite if you happened to have your fingers on the line when someone rang in. I don’t think these old phones had a local battery or power supply. Everything came directly from the exchange in a pretty brute force (compared to modern day) manner So it might not be quite as straightforward as connecting a battery and button. Some ex PMG (as the organisation was known then) people with a good memory might be able to shed some light on exactly how this setup worked. Cheers Bob ---
**Author:** ![Jason252557](https://avatars.discourse-cdn.com/v4/letter/j/97f17d/32.png) [@Jason252557](https://forum.core-electronics.com.au/u/Jason252557)\ **Post date:** [15 July 2023 21:36 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582/3 "2023-07-15T21:36:20Z")
Thanks Bob ---
**Author:** ![Fractal](https://avatars.discourse-cdn.com/v4/letter/f/2bfe46/32.png) [@Fractal](https://forum.core-electronics.com.au/u/Fractal)\ **Post date:** [16 July 2023 01:33 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582/4 "2023-07-16T01:33:58Z")
If you have ever seen an old magneto telephone the rotating handle on the side drives a massive ring generator inside the box. I recall it was an AC voltage of around 100V (60V - 105V) and a frequency of 20Hz. Enough to give you a nip so take care. So you need to get a “modern” ring generator which looks a bit like a small power supply and I am not sure if you can still buy them. Decades ago they were popular projects in electronic magazines. Note the ringer will not work on 50Hz. ---
**Author:** ![Jeff105671](https://yyz2.discourse-cdn.com/flex028/user_avatar/forum.core-electronics.com.au/jeff105671/32/3729_2.png) [@Jeff105671](https://forum.core-electronics.com.au/u/Jeff105671)\ **Post date:** [16 July 2023 03:01 UTC](https://forum.core-electronics.com.au/t/pmg-telecoms-bell-get-it-working/17582/5 "2023-07-16T03:01:39Z")
The device you are after is a 20Hz 100V ringer. See, for instance: [Pylon RG-10 400 Type Ringing Generator 20hz 105vac .10A Output Tested 52V Input | eBay](https://www.ebay.com/itm/265735945097) or [Tele-Q Phone Ring Generator (musson.com)](https://www.musson.com/tele-q-phone-ring-generator.html) If you can get the details of those devices you could work out how to build your own. Generating a sine wave that is adjustable from say 20Hz to 60Hz is reasonably straightforward, and an amplifier/transformer could boost it to the required voltage. Note that 50Hz mains won’t work, and trying to half-wave rectify to get 25Hz probably isn’t worth the effort. But before doing anything it would be worthwhile checking the continuity of the two coils - if they are open circuit rewinding them would be an interesting(!) job. I suspect replacements would be unobtainable.