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Old 24th Oct 2018, 1:17 am   #1
angelapantus
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Default Help with Gecophone 67

I have a gecophone 67 that makes a loud clicking noise when the dial is turned and when the receiver is replaced. It also needs a new handset cord. I only know how to rewire and replace the handset cords on gpo 300 series phones. Would be most grateful for any advice.
Sorry
should be Gecophone 47, the desk type that looks similar to a gpo pyramid but with internal bells.
Angela:
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Old 24th Oct 2018, 11:03 am   #2
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Default Re: Help with Gecophone

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Originally Posted by angelapantus View Post
I have a gecophone 67 that makes a loud clicking noise when the dial is turned and when the receiver is replaced.
You need to clean your 'dial off-normal' contacts! They're the ones that should close when the dial is turned. I'd just clean ALL the dial contacts by drawing a piece of blotting paper (or paper of similar roughness) through them when they're gently squeezed together. You can check with a multimeter on 'Ohms' whether they're clean as they should show a low resistance. Dirt can build up to tens, or even hundreds of ohms and this will cause clicking.

Use a drop of isopropanol or pull a 'spec-wipe' through between them.

Is handset not just a 164-type three wire handset same as on a 300 instrument but with GEC stamped on it? Cord replacement is similar (says he without looking at his Gecophone) with a whipped loop attached to the metal plate at the mic end where the pin contact is screwed into.
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Old 26th Oct 2018, 12:54 am   #3
angelapantus
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Default Re: Help with Gecophone 67

Hi Russel, many thanks for your most welcomed advice.
I used a piece of very fine sandpaper inbetween the dial contacts as I had no blotting paper. I also lightly oiled with clock oil and a cotton bud. Is isoproponal the same as rubbing alcohol? I do have rubbing alcohol, would that do? The phone does ring when I get incoming calls; does that mean the line cable is ok? It does need the handset cord replacing though. I just need to know how to replace it. Would I still need to use a rectifier and resistor
Like I would in a GPO 300 type? I would be most grateful if you could post some instructions.
Many thanks and kind regards
Angela

PS. I forgot to mention that the handset does have GEC written on it in the recess bit of the handset
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Old 26th Oct 2018, 9:19 am   #4
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Default Re: Help with Gecophone 67

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I used a piece of very fine sandpaper inbetween the dial contacts as I had no blotting paper
I wouldn't put sandpaper, very fine or otherwise, anywhere near a dial or switch contact! You'll've removed any silver plating by doing so and this will lead to more problems in the future with pitting and burning. One set of DON contacts shunts the dial contacts with a CR circuit to suppress any arcing caused when dialling. Even a diamond spatula used for relay and contactor cleaning is too rough.


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Originally Posted by angelapantus View Post
I also lightly oiled with clock oil and a cotton bud.
You'll get away with this in the short term, but it really isn't difficult to remove the dial and lubricate it accordingly with a thin wire and light clock oil, as per the instructions here: http://www.britishtelephones.com/tel%20auto%20b5125.htm

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Is isoproponal the same as rubbing alcohol?
Not sure. I use isopropyl alcohol. Vodka might do at a push. It works with camera lenses!

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Originally Posted by angelapantus View Post
The phone does ring when I get incoming calls; does that mean the line cable is ok?
It sounds like it, Angela. Has the telephone been converted to plug and socket?

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Originally Posted by angelapantus View Post
It does need the handset cord replacing though. I just need to know how to replace it. Would I still need to use a rectifier and resistor like I would in a GPO 300 type? I would be most grateful if you could post some instructions.
There are a few variations on the Gecophone and if you could identify the paster diagram appertaining to your instrument it would help greatly. There's an instruction on Bob's telephone pages here: http://www.britishtelephones.com/gec/gecodiag.htm

Generically, you need the rectifier across the receiver terminals - it will clip off excessive loudness, and you may or may not need a 3k3 resistor in series with the bell movement; it all depends on whether you intend using other instruments on the line at the same time.

The handset lead is simply a case of wire-for-wire replacement, and unpicking the whipped cotton loop at each end. Do you have a replacement handset lead to go on? Has it got cotton loops on it? There's a chap over on the Telecommunications Heritage Group who manufactures cotton-covered replacement leads and cabling for old telephones, but they are available from other sources. What does the end of the cable you are going to fit look like, if you have it?
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Old 27th Oct 2018, 12:01 am   #5
angelapantus
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Default Re: Help with Gecophone 67

Hi Russell, many thanks for your prompt reply. I hope the dial doesn't suffer any damage in the long term because of me stupidly using a fine sandpaper; just goes to show what a complete novice I am. I don't feel competent enough to risk removing the dial. I have now used a thin wooden spatula, wrapped kitchen roll round it and dipped it in rubbing alcohol which is isopropyl and rubbed back and forth between the connectors; Left to dry then did the same again using a few drops of clock oil. The dial is turning smoothly forward and back as it should. In fact better than it was before as it was just a tad slow. Thank you for the link to the gecophone diagrams. My model was there with instructions and diagram. There is a line cord in situ but wasn't wired correctly; I've now resolved that and replaced the handset cord. The instructions said to fit a 205 rectifier between T 5&6 green & red of handset cord, and a 3.3 resistor between L1 & E of bellset. I have also replaced the old mic with a 21a and the P1 with a P2 and 25 diapragm. The phone is now fully functional with clear incoming and outgoing speech. I just hope that the dial will be ok in the long term.
I can't thank you enough for your very helpful advice.
Best wishes and kindest regards
Angela
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Old 27th Oct 2018, 7:57 am   #6
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Default Re: Help with Gecophone 67

Hi Angela,

A good job done by the sound of it! Your dial should be OK but keep an eye on it and if starts running slow, just clean it again. I'd get hold of an old dial, if you can, just to play with. Thay're not that tricky really unless you do a complete strip down, when they can induce minor swearing.

I retrieved my Gecophone from the shed for a look in case you needed a 'talk-through'. Mine is about 1943 vintage with the blunter handset rest than the 'stags answers on the earlier models and is the simple one-capacitor version with the small induction coil. But I'm aware of its provenance and it wtill works fine with orig, carbon mic. I have a resistor in mine but no rectifier.

Pleased you got sorted, anyway. They're an nice instrument.
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Old 27th Oct 2018, 8:41 am   #7
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Default Re: Help with Gecophone 67

Meant to say... There's no need to oil the dial contacts. Oil is an insulator and whilst it's good practice to apply the thinnest smear of Vaseline (Petroleum Jelly) to electrical power contacts, it's not a good idea on telephone equipment contacts, as sticky lubricant will attract dust and gunge over time, even in the cleanest environment, and will build up a high-resistance barrier.
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