News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

BTMC 2714 A-RB - all nickel

Started by wds, September 24, 2013, 01:55:40 PM

Previous topic - Next topic

wds

bought this off of Etsy.  All nickel, and really sharp.  Sorry about the pictures, but all I have right now is my phone camera - I'll switch out the pictures tonight.  According to the catalog, the 2714A might have had a separate ringer, but I can't find any reference to the 2714-A-RB.  I'm sure the printed circuit board was added later on.  The plug is an Ethernet plug, RJ45.  Nice looking phone.
Dave

twocvbloke

Quote from: wds on September 24, 2013, 01:55:40 PMI'm sure the printed circuit board was added later on.

I can guarantee that it was, it's a GPO 746-type PCB, slightly modified to keep the capacitors flat, and the plug itself looks like a BT plug with the clip missing, so it must have been modified here in the UK to work as per a converted GPO phone... :D

wds

I switched out the pictures.  Hooked the phone up and it works great.  There are 3 wires on the line cord, red - blue - white.  Not sure what the third wire is for.  I had a little trouble getting the bell to ring, I wonder if the 3rd wire is for the ringer? 
Dave

Doug Rose

Dave...outstanding phone. Sure is a beauty...Doug
Kidphone

LarryInMichigan

It looks like you really hit the jackpot again. 

Larry

wds

Thanks, I'm pretty happy with it.  I'm pretty sure the phone originally didn't have any internals, and required a subset.  So even though the network card isn't original at least now it can be used as a normal phone.  Would like to get a schematic for that board so I could figure out the ringer.
Dave

twocvbloke

In the phone's cable, the White and Red are your Red and Green respectively, and the Blue is usually the ringer wire, but that can be eliminated as it appears to have a ringer cap fitted inside the phone still... :)

Just rewire it to this diagram:

http://www.samhallas.co.uk/repository/n_diagrams/0000/N846.pdf

And it'll get that bell ringing, even if it's one of them cheap chinese things that don't sound right... :D

wds

I tried every terminal on the PC board, and could not get the ringer to work.  I don't think there is a condenser on the PC board.  There were plenty of empty terminals, so I wired in a condenser and it works fine now.  The condenser looks like it was always a part of the board.  I hate to put a phone away that doesn't work 100%. 
Dave

twocvbloke

Quote from: wds on September 25, 2013, 07:01:07 PMI don't think there is a condenser on the PC board.

There are two, the blue things on wire tails, one on C3 (0.9uF standard) and one on C2 (1.8uF standard, C2 being the ringer capacitor, occasionally C3 aswell if they only had 0.9uF caps to hand so 2x to make 1.8uF), so it has the caps, I can see that some straps are missing though, which would prevent operation of the ringer, they would need to be fitted (or at least pieces of wire to do the same job)... :)

Just read the diagram I linked to and connect it all up as per the layout and it should work without any additional parts (aside from the straps), the GPO 746 is a simple phone, and even with part of it being used in a different phone, it should still wire up the same (not sure about the dial though)... :)

wds

Ok, I'll give it another go tonight.  Just to be sure, I'm using figure #1.  Looks like I need to remove the strap from T6-T7 and T8-T9.  Then place the ringer across T7-T8 ?
Dave

twocvbloke

Yes, Fig.1 is the correct one (standard wiring for a regular 746, the others are for party lines & PBX use), but the wiring as it is is rather jumbled up compared to the proper diagram, things are going where they're not meant to, someone seems to have just rewired it on the fly rather than look at the diagram to lay it all out correctly...

It'd be far easier just to rewire from scratch, as the wiring is rather odd that it'd be a case of the blind leading the blind, there's some oddities that would need to be addressed (such as the 2-wire hookswitch, the PCB usually uses 5, but only 4 are needed for standard wiring, and the 4-wire dial, the GPO dial uses 5), that PCB is pretty forgiving when it comes to wiring it up in all kinds of configurations, but makes it hard when it's a non-standard job!! :o