Orchid 416 PBX and old phones

[els1967]

Hello all, I’m a bit new to this so I hope someone can help.

I’ve dabbled a bit with old phone’s doing some minor conversion work on bellset’s and 332’s but nothing much more than following simple instructions I’ve found out on the internet. I’ve done three phones and so far I’ve been very lucky in that they have worked as expected. Recently I found an old Orchid 416 PBX going cheap on eBay so I bought it and rigged it up in my house with modern phones and it’s working pretty well. It say’s in the instructions if you want to get a ringing signal to an older phone each extension socket must be a master so I’ve de-soldered a 1.8uf 250v cap off an old master socket and patched it in but when I connect any of my old phones the ringing signal is very, very weak, just enough to “tickle” the bells. I know they old phones worked fine on the BT line so it can’t be to do with the phones.

Any idea’s about what’s gone wrong would be gratefully received.

[WreckTangle]

Does your PABX ring a late model BT 8746 handset properly? If so, your problem may be due to the lower impedance bell coils in the older handsets which will give them a higher REN value. You can modify by wiring a suitable resistor in series with the original coils or by swapping it for a later 4K ohm coil.

Your old bell phones should already have a ring capacitor in them unless you have bypassed it when converting them to plug/socket operation. It shouldn't do any harm to add one to the sockets so well.

[Station X]

Originally Posted by els1967

I’ve de-soldered a 1.8uf 250v cap off an old master socket and patched it in

Where exactly did you patch it in? If it's at the PBX you'll need to provide a ringing wire from there to the phone (three wires in total).

Why not just use a master jack to plug a converted phone into, or wire an unconverted phone to the PBX's A and B wires.

[els1967]

Originally Posted by WreckTangle

Does your PABX ring a late model BT 8746 handset properly? If so, your problem may be due to the lower impedance bell coils in the older handsets which will give them a higher REN value. You can modify by wiring a suitable resistor in series with the original coils or by swapping it for a later 4K ohm coil.

Your old bell phones should already have a ring capacitor in them unless you have bypassed it when converting them to plug/socket operation. It shouldn't do any harm to add one to the sockets so well.

Hi mate, thanks for that, but I don't really fully understand it. I don't have a 8746. When I converted the bellset 1a I used 3.3k resistor. Looking inside it it has 1uf cap in there.

Originally Posted by Station X

Where exactly did you patch it in? If it's at the PBX you'll need to provide a ringing wire from there to the phone (three wires in total).

Why not just use a master jack to plug a converted phone into, or wire an unconverted phone to the PBX's A and B wires.

Hi mate, yea I did put in a ringing wire so my extns. would work with my old phones pre fitting the PBX. I put the 1.8uf cap in by use of a "Krone" connector block (not sure what the right name is for them) that I used to connect my extn wiring to the PXB so it's not actually in the tele socket. I used small modular type sockets as I wanted to fit cat6 at the same time so I went for secondary sockets as I didn't really plan to have a PBX when I started out.

[els1967]

Just by way of an update, I tried taking the 3.3k resistor off the bellset and there was a slight improvement, not a vast amount though. Wrecktangle, I did find an 8746G I had forgotten about buried up in my attic but still much the same thing, very slight ring but no much else. I read the voltage across the blue and white cable and get 60v on the PBX and about 80v when on the BT line, which rings quite nicely. Any idea's gratefully received as I really though fitting a PBX would fix all these issues with REN numbers/bells not working.

[WreckTangle]

So it sounds as though you have tried to put a 1.8uF capacitor between the cables to pins 2 and 3 at your TJF. That is non-standard to say the least. It would be important not to transpose A and B (2,5) between the frame and the socket for this to work properly. If you're using Cat 6 why not just buy a PABX master RJ45 balun? Then you'll only need to wire a single pair from the PABX and polarity won't matter.

Just as a matter of interest, have you tried an unconverted master bell set? That would probably work without needing the bell shunt. Add the resistor if your PABX doesn't have enough power to ring the bell.

[els1967]

Hi mate, I did put up a post a while back about various things I did try today but it seems to have got vaporised. Thanks for the info and I'll write a proper reply tomorrow.

[dagskarlsen]

The REN booster in mention will probably not help you, the Orchid pabx gives you ring voltage of 65V at 50 Hz. The old ringers do not like, but may sometimes ring at 50Hz.

I do have an old Ericsson pabx ringing at the same parameters, and it was a pain, so I changed to a UK version of the Panasonic KX-T 616.

The orchid uses US plug configuration, and that is good for old telephones, 2 wires, and a capacitor in each phone.

If we look at the ringer circuit, you should have a capacitor of usually 1, but somtimes up to 2 micro Farad. rated at 200V or more, and non polarized. in series with that you get the ringer motor, often made of 2 coils. (no resistor!)

The next will be to adjust the ringer to cope with 50 Hz. some ringers has a screw to loosen and pull the ringer together to be shorter, do so and adjust so the maximum movement of the hammer will be approx 4-5 millimeters. Follow up with adjusting the gongs so it is a distance between gong and hammer as small as possible without touching when hammer is in position near the bell.

This will make most old ringers work at 50Hz.

dsk

[els1967]

Hi mate, thanks for that, just tried it on a 746 and it worked quite well. Will have a look on some of my older phones later.