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Old 28th Dec 2017, 10:15 am   #21
Bigdaz101
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Default Re: GEC 1000 phone not working properly?

This is at my house
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Old 28th Dec 2017, 10:29 am   #22
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Default Re: GEC 1000 phone not working properly?

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Originally Posted by Bigdaz101 View Post
'and there was no reading on hook, I’ll test it at my mums next time I’m there'
Interesting... You should read a nominal 50V d.c. across the line with the telephone on-hook. This is the d.c. voltage across the incoming line pair to the premises.
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Old 28th Dec 2017, 10:31 am   #23
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Default Re: GEC 1000 phone not working properly?

This is how I've connected my Ericsson N1026A (similar to yours) and it works.
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Old 28th Dec 2017, 10:33 am   #24
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Default Re: GEC 1000 phone not working properly?

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Ok my mistake I had the multimeter on the wrong setting on hook 50.2v off hook 4.2v
Phew! Now check at your mum's. 4.2V is a wee bit on the low side but should still work with a carbon mic in place. I was expecting something more like 8 - 12V. If your phone has a T21A electret mic insert and the off-hook voltage is too low, the mic will not work. They need at least 4.5V to drive them.
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Old 28th Dec 2017, 10:49 am   #25
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Default Re: GEC 1000 phone not working properly?

Note, however, that the 'off-hook' d.c. voltage will change from (typically) 8V 'fresh' off-hook (dial tone) dropping to 5V (typically) when 'number unobtainable' tone cuts in, and will sit (typically) at 8.5V when a call is initiated.

These figures are from my BT line using a 332 telephone.
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Old 28th Dec 2017, 11:12 am   #26
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Default Re: GEC 1000 phone not working properly?

Looking at the diagram it says on note 4 to fit a 100ohm Resistor for reduced volume which mine has so my guessing by fitting a 300ohm resistor like it says on the diagram it will increase the volume,
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Old 28th Dec 2017, 11:22 am   #27
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Default Re: GEC 1000 phone not working properly?

Ok I had a better mic fitted so it would work better was my plan, I don’t know what mic it is but here’s a photo, what would cause the voltage to be to low ? I have a 332 also that has the original mic so next time I go to my mums I’ll test the voltage and the other phone,
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Old 28th Dec 2017, 11:24 am   #28
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Default Re: GEC 1000 phone not working properly?

Here’s the new mic
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Old 28th Dec 2017, 11:47 am   #29
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Default Re: GEC 1000 phone not working properly?

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Ok I had a better mic fitted so it would work better was my plan, I don’t know what mic it is but here’s a photo, what would cause the voltage to be to low ?
I don't know what equipment Sky uses at the exchange that may be different and cause a reduced voltage line-loop at the customer's end. The spec will be on BT SINET somewhere, and I would've thought they (Sky) would have to comply.

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I have a 332 also that has the original mic so next time I go to my mums I’ll test the voltage and the other phone,
Excellent plan. If your 332 works satisfactorily with the carbon mic then you're onto something. A good carbon mic will work well in your GEC1000 so don't be afraid to fit one. I would also be inclined to short out that resistor between terminals 4 and 2 on the dial block (the reduced volume one) altogether.

Does your mum live a long way from the exchange?
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Old 28th Dec 2017, 12:11 pm   #30
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Default Re: GEC 1000 phone not working properly?

My mum lives in a village miles from anywhere, so I’ve no idea where the exchange is, I’ll short the low volume thing out and see how that improves the volume
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Old 28th Dec 2017, 12:12 pm   #31
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Default Re: GEC 1000 phone not working properly?

That certainly looks like an electret transmitter inset 21A. As Russell says, the off-hook line voltage may be marginal for it to operate.

If you have a 300Ω (or more probably 330Ω as a standard value) available, there would be no harm in tryin the substitution, but I can't see that doing so would increase the operating voltage of the transmitter.
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Old 28th Dec 2017, 12:14 pm   #32
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Default Re: GEC 1000 phone not working properly?

If increasing the resistance is supposed to increase the volume, I don't think shorting it out is going to be productive.
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Old 28th Dec 2017, 12:31 pm   #33
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Default Re: GEC 1000 phone not working properly?

I removed the resister and put a piece of wire in its place and no dial tone so I’ll get a 300ohm one instead,
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Old 28th Dec 2017, 1:11 pm   #34
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Default Re: GEC 1000 phone not working properly?

Will this type of mic fit ? If not can someone help me with what will fit as I have no idea what was fitted originally, the one from the 332 won’t fit,
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Old 28th Dec 2017, 1:19 pm   #35
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Default Re: GEC 1000 phone not working properly?

Here’s a photo I’ve found online
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Old 28th Dec 2017, 2:00 pm   #36
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Default Re: GEC 1000 phone not working properly?

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If increasing the resistance is supposed to increase the volume, I don't think shorting it out is going to be productive.
D'oh! Misread it!
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Old 28th Dec 2017, 2:14 pm   #37
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Here’s a photo I’ve found online
That won't fit. You need an 'Insert No:13'. You'll also need a sprung pin to fit in the back of the mic to attach the wire to, and your mic will need to be a version with a stud attached around the periphery of the 'flying saucer' to fit the other lead to. The GEC1000 and the original 706 instruments had these mics fitted as well as the 300 series instruments.
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Old 28th Dec 2017, 2:25 pm   #38
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Default Re: GEC 1000 phone not working properly?

So I need to speak to the chap that fitted it and hope he still has them,
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Old 28th Dec 2017, 3:00 pm   #39
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Default Re: GEC 1000 phone not working properly?

are you sure ? From what I’ve seen online this is a type 3 handset which takes the number 16 microphone,
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Old 28th Dec 2017, 4:48 pm   #40
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Default Re: GEC 1000 phone not working properly?

If that's the handset you have, I think you are correct about the inset no. 16. I was expecting (and I assume Russell was too) that your 'phone would be fitted with handset no. 164 into which the insets shown by Russell would fit.
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