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Surprisingly cheap straight-corded handset WE 500...

Started by twocvbloke, August 29, 2017, 12:10:02 PM

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HarrySmith

Nice phone! Almost completely dates matching! What are the dates on the cords? Those are some really strange plungers.
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

twocvbloke

Quote from: HarrySmith on September 01, 2017, 08:12:58 PM
Nice phone! Almost completely dates matching! What are the dates on the cords? Those are some really strange plungers.

They're both stamped "54", so match the phone... :)

As for the plungers, like I say I think someone bodged those together out of some other plastic pieces, don't know why, but, that's a part of it's history I guess... :)

On a side note, I noticed that one side of the shell seems to have bulged out, presumably where it hadn't been refitted correctly, haven't a clue how I'd go about fixing that at the moment, it's probably been that way for many years...

19and41

Those plungers ought to be easy to find.  My birthday phone '56 base, '54 shell, uses black conventional plungers.  That phone's going to look nice.
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke

andy1702

That's a nice phone. I guess I must have misse that one!  ;D I found three similar phones a few months back. http://www.classicrotaryphones.com/forum/index.php?topic=18475.0

Also, just for the record, here's a video of how to fit a UK line cord to a 500. As far as I'm aware there's no need to use a resistor (as some suggest) because these are rated REN 1 anyway. https://www.youtube.com/watch?v=F73oMJunPHY
Call me on C*net 0246 81 290 from the UK
or (+44) 246 81 290 from the rest of the world.

For telephone videos search Andys Shed on Youtube.

twocvbloke

Yeah, I've got a couple phones wired for use on UK lines, I just connect the A & B to L1 & L2 and of course move the black ringer wire to L1, just my reference to keep it as a 2-wire phone... :)

I'll note that your video shows that the phone you wired up was also wired for 2-wire as the black ringer wire was on L1 already, so the blue Bell wire on G was basically just terminating it to an empty terminal, as G is just an external strap terminal as far as I'm aware and doesn't connect to anything inside, A and K internally have the capacitor (I think it's 1.8uF, just like GPO 700 series phones) which is wired across one of the ringer coils (there's usually two coils in these type ringers, one small one, one large, but I forget which wires are for what!), which is then wired in series with the other coil making it a 4kOhm(ish) coil with an inline ringing capacitor... :)

ThePillenwerfer

I quite agree about there being no need for a resistor as the 500's bell coils add-up to 3650Ω.  The capacitor is, however, 0.45µF or at least it is on the diagram I found.

twocvbloke

You're probably right there, I haven't looked at the circuit diagram for a 425B for a while, so probably a lot lower than 1.8uF!! ;D

Infact, I just opened my Cortelco 2554, and it's ringing capacitor is 0.47uF, so, yeah, not 1.8!! ;D

andy1702

Quote from: twocvbloke on September 02, 2017, 05:00:20 PM
I'll note that your video shows that the phone you wired up was also wired for 2-wire as the black ringer wire was on L1 already, so the blue Bell wire on G was basically just terminating it to an empty terminal, as G is just an external strap terminal as far as I'm aware and doesn't connect to anything inside, A and K internally have the capacitor (I think it's 1.8uF, just like GPO 700 series phones) which is wired across one of the ringer coils (there's usually two coils in these type ringers, one small one, one large, but I forget which wires are for what!), which is then wired in series with the other coil making it a 4kOhm(ish) coil with an inline ringing capacitor... :)

Well spotted! I gues sthat was a half deliberate mistake on my part. What I actually did was test the wiring on one of the other phones (all three came together) which had the black wire on G and didn't ring when I left off the blue connection. Then I used a second phone for the video production, which as you rightly say, already seems to have had the black wire moved.

I don't really see as it matters which way you do it. The only thing I will say is maybe it's best to use the cap in the wall socket if it's an old phone where the internal cap might be a bit dodgy. Having said that, I don't recall seeing a phone with a cap in it that's so bad it doesn't work as it should.

Andy.
Call me on C*net 0246 81 290 from the UK
or (+44) 246 81 290 from the rest of the world.

For telephone videos search Andys Shed on Youtube.

twocvbloke

Technically speaking, with Bell wire on G with the black ringer wire, the capacitor built into the network is still in circuit (through A and K), so you have both the Master socket cap and the built-in one running at the same time, you could just move one of the wires on A or K and join them together, but, like I say, I just wire it up as 2-wire, given BT-Openreach (or whatever they are now) keep installing master sockets and faceplates that cut out or just aren't fitted with a bell capacitor, it makes it a lot easier to make a universal telephone... :)