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Old 2nd Sep 2017, 10:58 pm   #1
bakophone
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Default Bell Tinkle when dialing 332 telephone

I have just made a standard conversion on a 332 telephone as I have with many others, however with this one, on dialing out the bell always tinkles.

I have tried swapping the dial, the line cord , re-adjusted the receiver points and re-checked the dial wiring, but none of this has made any difference. In the past when I had this issue on another chassis I ended up just used an alternative one.

Does anyone know whether there is a simple fix to this, I wondered whether it could be a fault with the original capacitor?

Thanks
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Old 2nd Sep 2017, 11:49 pm   #2
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Default Re: Bell Tinkle when dialing 332 telephone

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Originally Posted by bakophone View Post
I have just made a standard conversion on a 332 telephone as I have with many others, however with this one, on dialing out the bell always tinkles.
Have you checked continuity of the wire from T11 to pin 4 on your BT standard plug (mates with term. 3 in the LJU)? A break here would open the spark quench / bell shunt circuit, via the DON contacts, the 30 Ohm non-inductive resistance winding on the ASTIC and the capacitor in your master LJU, and may give rise to 'tinkle'.

Are your DON contacts clean? Is the 30 Ohm resistance intact? Does another telephone work tinkle-free on the same circuit?
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Old 3rd Sep 2017, 12:28 am   #3
bakophone
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Default Re: Bell Tinkle when dialing 332 telephone

Thanks for your suggestions, I have cleaned all the contacts (twice!) and swapped the line cord so don't think it is continuity to T11. As you suggest I will check the the 30 Ohm resistance in the ASTIC as this could well be the problem.

I have other Bakelite phones working on the same circuit without problem so don't think it is the house wiring.
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Old 3rd Sep 2017, 8:12 am   #4
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Default Re: Bell Tinkle when dialing 332 telephone

Is the cradle-switch making good contact when handset is off-rest? The one between the 30 Ohm resistor and T11? Can you check with an ohm-meter and operate the cradle switch?

It may be that although you've cleaned the contacts, there may still be a break on a wire or a joint, say. I'd be going round the loop from T1 to T13 to T11 with an ohm-meter and the handset off-rest to check.
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Old 3rd Sep 2017, 5:53 pm   #5
bakophone
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Default Re: Bell Tinkle when dialing 332 telephone

I've looked again at the phone and checked the connection fron T11 to ASTIC 6 which was fine, however there was no resistance or continuity between ASTIC 5 and 6. I've now connected a 30 ohm resistor between these terminals and the bell tinkle has disappeared. Hopefully I'll remeber this the next time it crops up!

Thanks for your help with this.
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Old 3rd Sep 2017, 6:02 pm   #6
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Default Re: Bell Tinkle when dialing 332 telephone

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Thanks for your help with this.
You're welcome. Pleased you got it sorted! Wonder how it came to be open-circuit in the first place? I've known bell-bobbins go O/C but not ASTICs. With any luck it will be at the end of the winding where it terminates and you can set it aside for a rainy Sunday or whenever.

I don't know how the 30R winding sits physically within the coil, but are there any dings, possibly caused by an errant screwdriver, around the coil covering?
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Old 4th Sep 2017, 10:53 am   #7
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Default Re: Bell Tinkle when dialing 332 telephone

I've had a similar problems with the astic coils, out of the 20 or so phones I've restored I've had the problem twice, and solved it exactly as above. I once steamed off the paper to take a look inside the coil but everything looked ok, so I can only assume the breaks (in my case) have been buried deep within the windings.
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Old 4th Sep 2017, 11:02 pm   #8
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Default Re: Bell Tinkle when dialing 332 telephone

There was no obvious external damage to the ASTIC, however it did look like someone had been doing some home wiring on this chassis in the past so may have blown the winding when doing this. I have had issues with ASTIC coils before but normally it has been due to lack of dial tone rather than bell tinkle.
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