I spotted this the other night only about half an hour after it had been listed. The price was less than it would be worth in bits so I bought it.
https://www.ebay.co.uk/itm/183193741441
It arrived today and has more damage than was declared. As well as the broken 'horn' there's a chip out of the base and the earpiece has a small nibble out. I don't know what's happened to the 'tee bar:' it seems to have simply degraded and has become extremely brittle. Inside the induction coil is AWOL. The dial was very stiff but that was an easy fix as it wasn't damaged, just in need of servicing. All the terminal screws have been nicked though.
Replacement parts can be had, either second-hand old ones or modern replicas, but these don't come cheap and simply buying and fitting parts isn't much fun.
I've patched up Bakelite before so that didn't hold any fears and as regards the coil, like James Blunt "I won't loose no sleep on that 'cause I've got a plan:" a plan that will have those who bother about Originality and Authenticity hopping up and down with ire.
The first thing to do was fit some supports for the filler and then get that on. When that had cured I could roughly shape it. It will need more and refining better but my dinner is calling unto me.
Good job...very clever!
Keep us posted...
I am anxious to see the results. My bakelite repair skills are horrible at best.
Larry
Man. keep the pics and updates coming!
I wanna see this one done too!
interesting how each technique is different, but produces such awesome results!
maybe some of that talent will rub off on me???
what goo are you using?
The "Goo" is a car filler called David's Isopon P38. I'm pretty sure that it's the same as Bondo in the US.
Quote from: ThePillenwerfer on April 26, 2018, 01:29:54 PM
The "Goo" is a car filler called David's Isopon P38. I'm pretty sure that it's the same as Bondo in the US.
Isopon, crikey, that's a product I haven't heard/used in a long time. Totally forgot about that stuff.
I'm interested to know how you managed to get such a good shape, and what you are going to use to match in the black?
Excellent work so far, nice thread.
I've seen similar damage on 'tee bars' too. I don't know why they should degrade differently to the rest of the phone.
Nice work. I like how you put a piece of metal in for added strength. Good thinking.
I shaped the first lot of filler with a file, then more applied where needed and filed again. This time I finished off with sandpaper.
I've now sprayed the filler. The photograph isn't brilliant as it's been dull and raining all day so not conducive to photography.
The paint should be fully hard by tomorrow so I'll then be able to blend it in with the surrounding Bakelite. I say "Bakelite" but I strongly suspect the the cradle is ABS. I know that the GPO were still refurbishing these 'phones into the 1960s so they may have changed-over before they stopped. Of course given that it's had other parts nicked the original could have been swapped with a damaged reproduction.
Are you sure the coil is missing? I'm not familiar with this exact type, but I thought most of the internals of these were inside the bellset rather than the phone, in the same way that candlesticks have almost nothing inside them.
The way to check if any parts are ABS is to put a spot of acetone in a hidden bit somewhere. If it turns the surface sticky then it's almost certainly ABS. ABS wasn't used on UK telephones until about 1963 though. If it's bakelite the acetone will do nothing much.
The 162 was the first 'phone this shape and that did indeed have the induction coil in the bell set. The 'phone itself did have an anti-sidetone transformer though.
When the 232 came out this was fitted with a full anti-sidetone induction coil. As they didn't have an internal bell or capacitor they were still used with a seperate bellset.
I didn't know that. I've learned something interesting there.
I've just about finished this now. It still needs a final polish, a line cord fitting and a dial label printing.
The correct induction coil for this would be a No 27. These are easily available and not too expensive but I decided to have some fun and fit a No 32 as used in the much later 746. I had to make a PCB to mount this which took a bit of working out how best to squeeze it in.
The circuit of the 746, and the 706 before it, differs in that the handset is connected with a four- as opposed to three-core cord. The receiver also has a lower resistance. I don't know if that would matter in the real world as for all that the RESISTANCE is lower I don't know about the IMPEDANCE. This 'phone had one of the early No 1L receivers. These are appalling: they sound so tinny that they nearly loosen your fillings. The GPO came out with a better version, the 2P, during the 1950s which are as good as anything that's been made since. However to get the best out of one of those you really need to change the earpiece as well, from a No 18 to a No 23. What I did was remove the guts of the 1L and put a 700-sereis 4T inside it.
After plaitting up a handset cord I put everything together and gave it a try. There was no sidetone. "Oh bother. How very vexing," I said, or fewer Anglo-Saxon words to that effect. I quickly found that I'd got a diode the wrong way around on the electronic transmitter I'd made. After correcting that it worked very well.
I wouldn't recommend this modification, especially if you haven't got an Induction Coil 32 laying around, as it's not really worth the trouble. It did however provide me with three days' entertainment. The only thing that couldn't easily be re-done properly is the modification to the receiver, and I think that would be possible.
As for the 'tee-bar' I tried sanding it smoother and the benighted thing snapped in half. I managed to fix it with epoxy and then put some filler on it and sprayed it. When I was filing/sanding it it felt very strange and there was also an odd smell coming off it. I'm wondering if it's actually made of celluloid. The handset is dated 1944 so wartime shortages could have meant that anything available was pressed into service.
Now that's clever! Any chance of a photo if the other side of the circuit board please? I think i can see what you've done from the diagram, but I'd quite like to see what it looks like in reality.
As requested.
Thanks for that. It's really clever.
Just a few questions (and maybe this is me just being a bit thick) but why have you got a blue connection to a line cord on your diagram? How does a bell box wire up to this? If you've wired it 746 style, then shouldn't there be a 3.3k resistor somewhere in series with the bells? Is that in the bell box so you left it off the wiring diagram for the phone?
There is no bell box; it just plugs straight into a socket. I can hear my 746 in the hall ring all over the house so don't need any more.
If it did have a bell box that would go between the blue and white wires and the resistor would be in there. I tend to un-solder the link between the two coils and put the resistor in its place as they look messy tacked onto the terminals.
Quote from: ThePillenwerfer on April 30, 2018, 04:14:58 PMI tend to un-solder the link between the two coils and put the resistor in its place as they look messy tacked onto the terminals.
I keep thinking about doing that with my phones, but I never do as I don't want to remove the originality...