Can anyone help identify this phone please?

[andy1702]

I got a box of bits the other day which contained a few semi-complete phones. I have no idea of the history of the parts, so don't know if the phones that are almost complete have been assembled using some bits from the others.

The photos show one of the more interesting examples. At first glance it's a bog-standard 706. But did grey 706s ever have the metal finger wheel? The whole dial mechanism is basically steel and brass.

Also look at the 'arrows' in the finger holes. They're not screen printed onto a bit of flat plastic like most of the 706s I've seen They are actually moulded into the back of a clear plastic plate, which is then painted on the back using the same metallic finish as used on 746 dials.

I know the alpha-numeric surround is probably the wrong colour. the phone didn't have one fitted when it arrived, but this one just happened to be floating around in the bottom of the box, so as i didn't have another one to hand I fitted it.

So my question is does this combination of parts look original or is it a 'bitsa' made by someone from a load of old spares?

As you can see, the base doesn't give many clues either.

Andy.

[AndiiT]

Hi,
Try the Ericsson and GEC sections here to begin with.

Further digging suggest it may be one of these (basically a Plessey version of the GPO 706)
Any chance of the picture of the innards?

Andrew

[andy1702]

None of those appear to have the metal finger wheel, so no matches as far as I can see. I'll take a photo of the inside tomorrow.

[AndiiT]

Hi,
I think that the early 706's had a metal dial but the number on the bottom suggests that the phone was from a private supplier.

A lot of people think that the GPO actually designed the 700 series of phones (although they probably did have some say in it) but the phones were made by a number of different manufacturers such as Ferranti (Pye TMC), Ericsson, Plessey, GEC etc. and then sold under license where the GPO designated their own type numbers to the phones.

For example the Ericsson N190o series were electrically identical to the GPO 706 and the cosmetic differences (if any) were minimal.

Regards

Andrew

[andy1702]

I'll have a root around inside it tomorrow and see if I can find any markings. The base is metal rather than plastic if that narrows it down any. Unfortunately it doesn't have a line cord, so we can't get any clues from GPO junction boxes etc.

[Nickthedentist]

Originally Posted by andy1702

None of those appear to have the metal finger wheel, so no matches as far as I can see. I'll take a photo of the inside tomorrow.

The one at the top of the Plessey page does, and the curvy finger stop that you see on 300-series phones too, like yours does.

[TonyDuell]

What do the gravity switch plungers look like? (the ones in the handset rest that are
pushed down when you put the handset on top of the the telephone).

Are the insides exactly as you'd expect for a 706? I've seen similar telephones with a resistor network in place of the regulator PCB, and even one (correctly) without the induction coil.

There are some photos of ones that I have worked on here :

https://www.***********/photos/tony_d...57634494119758

[andy1702]

It's looking a lot like a N1900. But the N1900 has a carrying handle and this phone doesn't. I'm off to take the internal photos, so I'll report back.

[andy1702]

I've taken a few photos of the inside now. Not much to see really. Note the absence of the regulator board though and a group of resistors where it should be. Also note the small resistor connected across the terminals. It was already in there and doesn't appear to be the correct 3.3k value for the normal conversion of a 700 series.

[andy1702]

Here are a few more images. There is a code moulded into the case and also an obvious mark on the inside where it looks like a wiring diagram was once.

[russell_w_b]

Can you look beneath the cable entry grommet for the handset and see if there's a manufacturer's stamp or number there? It'll be very small if there is one.

Assuming it has the original handset, of course.

[russell_w_b]

It may also be (if your instrument is as old as the dial suggests) that it has a case made from 'Diakon'.

http://www.britishtelephones.com/t706case.htm

[andy1702]

There's no markings near the cable entry on the handset. I've also had a look inside the ear cap and found it marked 26, which proves the handset at least is 'Diakon'. This seems reasonable as the handset is the proper grey and not faded to brown as the ABS phones do. However the main case IS faded quite badly, so either they were using up old handsets with new cases or the handset has been changed at some point.

So we now know the handset at least was manufactured early 1963 at the latest.

Does anyone know anything about the '3d effect' arrows on the dial?

Andy.

[TonyDuell]

Interestingly it seems to be based on the Mk2 706 (PCB, not hardwired). I am not one to know the dates of various telephones, but that might be another clue.

What is the dial mechanism? If you loosen the 4BA screw on the dial mounting -- the one that you get to from the left, which tightens onto the cradle metalwork, not the longer one on the clamp right with the head on the right -- the dial will pivot forwards and unhook from the cradle. You cna then just lift the bottom mouting tabs out of the bracket between the gongs. Is it a normal GPO dial, or more like an American one?

[andy1702]

I thought it looked a bit mk2-ish too. But didn't Mk2s normally come with the transparent finger plate?

When I opened it up the dial basically looks like a normal one. It seems to be the earlier all metal version though with brass and steel gears, not the plastic one as fitted to later phones. It does have the plastic dust cover on the back though.

[TonyDuell]

As far as I know there are 3 basic versions of 706 (which this telephone seems to be based on).

Mk1 : plastic base, hardwired
Mk2 : metal base, PCB, bell hardwired and fixed to PCB
Mk2a : metal base, PCB, connection between bell coils made by a PCB track

That last modification is a right pain IMHO. On the Mk2, you can remove the PCB and then undo 2 screws and take the bell mechanism out. On the Mk2a you have to desolder 2 connections (the track linking the bell coils) as well.

So the dial is GPO-like with the impulse cam on the centre spindle and a little follower that flips over when you dial and flips back to operate the contacts as the dial returns to normal. Incidentally, to get the dust cover off, remove the long 4 BA screw at the top (it is a lot easier to take it right out than just loosen it), take out the 6 BA screw at the bottom (if present) and remove the clamp ring (the reason for removing that 4 BA screw is that the wires can be passed through the gap in the ring so as to completely remove it rather than have it hanging on the wires and getting in the way. Then just pull off the dust cover.

I am not sure I can repeat the mnemonic for the order of the wires on the dial terminals on a family list like this one... I can send it by PM if anyone wants to know it...

I am pretty sure this not a normal GPO-issue telephone (lack of regulator for one thing), most likely it's from a PAX/PABX system. As a result there might well be a metal finger wheel (which would, I think be more robust, pehaps for industrial use) on a telephone as late as a 706 Mk2

[russell_w_b]

Made for export, maybe?

[andy1702]

It's certainly a bit of a head-scratcher, that's for sure! I think I'm going to try fitting a line cord and see if it works. I guess it should probably have a dark grey dial surround as well, rather than the sort of peachy coloured one it's got at the moment. As a matter of interest, does anyone know what the surround might be off? I've always understood these reverse painted surrounds don't discolour, so any ideas what colour phone it belongs to?

[AndiiT]

Hi again,
The presence of the resistor between T4-T5 suggests that someone may have had a bash at converting the phone in the past, however the strap T8-T9 should have been transferred to T17-T18 too in that case and it has not been.

The lack of a regulator suggests that the phone was probably intended for use on a PBX or PAX so will most definitely have been provided by a private supplier. It's still not beyond possibility that the phone has been a "mix and match" but the type number on the base is a bit of a mystery as the Ericsson type numbers all began 'N'.

You mention that your phone has no carrying handle, these were often fitted at a later date and as the type number begins with S it's probably not of Ericsson origin (as suggested above)

Regards

Andrew

[andy1702]

I think I'll replace the resistor with the correct one and do a proper conversion with a new line cord, then see if it works.The dial was almost seized solid when I got it. But a bit of oil, standing, then oiling again has got it moving at something like the right speed.

Andy.