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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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13th Jun 2012, 12:26 pm | #1 |
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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ATM 332 very low earpiece volume
Hi,
I have just acquired a vintage ATM 332 phone. It appears to be a genuine original. Inside looked undisturbed. Dust of ages, etc. This is the first antique phone I have worked on, so I am new to it all. After some initial cleaning, I converted/rewired it as per the very clear instruction on the antiquephones.blogspot.co.uk web site. It worked but the dial tone was very quiet. My wife then made a test call from her mobile and it rings very well, and transmits my voice at good volume, but the receive audio is also extremely quite. I assume it is likely to be a faulty/dunged up earpiece? I wanted to check out the earpiece, but unfortunately I can't remove the earpiece cover as is jammed (possibly cross threaded). It already has a hairline crack in it, so I am reluctant to use any force on it as it will probably just break. So... Is there anything else that might cause very low received volume that I could check first? Are there any known "receive volume problems" with phones like this? Ted. |
13th Jun 2012, 1:59 pm | #2 | |
Dekatron
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Location: West Cumbria (CA13), UK
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Re: ATM 332 very low earpiece volume
Quote:
It should be possible to judge visually whether it really is cross-threaded, but it is probably simply gummed up. It takes very little in the way of foreign particles in the thread to effect a significant increase in friction.
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13th Jun 2012, 3:29 pm | #3 | |
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Re: ATM 332 very low earpiece volume
Quote:
If audio present, look at the handset receiver - including wiring. If no, or weak audio present, report back.
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13th Jun 2012, 4:24 pm | #4 |
Dekatron
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Re: ATM 332 very low earpiece volume
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13th Jun 2012, 10:47 pm | #5 | |
Dekatron
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Re: ATM 332 very low earpiece volume
I have one of these in normal daily use. Try cleaning the diaphragm in the earpeice, (or turn it over) and make sure there is no swarf stuck to the magnet inside.
I don't think mine is an Indian one-and presumably the OP's, but more likely a non GPO(public network) one, such as was used on a switchboard or private network. Mine came from a Bristol hospital. Quote:
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14th Jun 2012, 8:33 am | #6 | ||
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
Quote:
I did put some lubricant on it last night. No sign of any movement this morning, but I will add a bit more and give it some more time to soak. Ted. |
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14th Jun 2012, 8:36 am | #7 | |
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
Quote:
Ted. Last edited by Dave Moll; 14th Jun 2012 at 10:46 am. Reason: quote fixed |
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14th Jun 2012, 8:46 am | #8 | |
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
Quote:
Inside the phone, the capacitor is stamped "GPO batch tested" (the stamp is smudged, but the GPO part is clear) and the impressed stamp on bottom cover appears to be a normal ATM mark. All wiring and soldering looks original and untouched. The paper label on the front of the dial has the Plessey symbol on it, so I assume it was one of their internal phones. Ted. |
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14th Jun 2012, 8:51 am | #9 | |
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
Quote:
I will try warming it (I have now put some lube on it to soak in as well) but as it has a hairline crack in the cover I am concerned that any force will cause the thin threaded part it to shatter. Ted. |
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14th Jun 2012, 11:02 am | #10 |
Dekatron
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Re: ATM 332 very low earpiece volume
One of those strap wrenches would be useful here, often sold for removing oil filters: http://www.toolstation.com/images/li...bbig/67000.jpg
Should the worst happen, spares do crop up on eBay etc. at reasonable prices. Nick. |
14th Jun 2012, 11:32 am | #11 | ||
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
Quote:
Just tried it, and the dial tone is quite a reasonable volume in a cheapo headphone, so it does look like it is the earpiece that is the problem. I'm still working on getting the cover off! Ted. |
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14th Jun 2012, 3:53 pm | #12 |
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Re: ATM 332 very low earpiece volume
One of those grippy rubber sheets used for pickle-jar tops, etc... may work best, or the back of a latex glove. Attempt to tighten the earpiece first - but not too far - then try unfastening it.
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14th Jun 2012, 5:20 pm | #13 |
Pentode
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Location: Winterton-on-sea, Great Yarmouth, Norfolk, UK.
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Re: ATM 332 very low earpiece volume
SUCCESS!
I finally got the earpiece cover off, and in one piece! After a long soak with some lube, a latex glove gave me the required grip. The real trick was the suggestion by Russell W. B. of attempting to tighten it slightly first. I then felt it move slightly, and was then able to unscrew it. The problem with the low volume was immediately obvious. The diaphragm had rusted to the magnet poles. A good clean-up worked and the volume is now just fine. Many thanks to everyone with their suggestions. I now have a good working phone, apart from a slightly "jumpy" dial which I will now tackle. Ted. Last edited by Dave Moll; 14th Jun 2012 at 7:28 pm. Reason: broken quote of preceding post removed |
14th Jun 2012, 6:15 pm | #14 |
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Re: ATM 332 very low earpiece volume
Pleased it worked, Ted, and you got sorted. You could put a little french chalk dust around the threads and it'll come apart easier next time.
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