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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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#1 |
Diode
Join Date: Oct 2021
Location: Plymouth, Devon, UK.
Posts: 6
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Hi
I've a number of BT Freeway No 3 A-H phones which I've not used in a long time and the batteries in the handset need replacing. This is the phone:- https://www.britishtelephones.com/cordles3.htm Has anyone changed the batteries in these and know how to get into the handset to do the job? I can't figure out how to open up the handset, there are no screws on the outside, its just pressed plastic. The front and back of the plastic handset are connected together down the length of the phone, but where as the top prizes apart a bit, it clearly doesn't want to open up the whole way down the phone and seems firmly attached lower down. The pastic on the front of the phone comes apart at the base but again doesn't seem to want to come apart all the way. Maybe I'm not being forceful enough in trying to part the plastic. Anyone who has got the handset apart and knows how to do it, I would appreciate a heads up. Thanks. |
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#2 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,538
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The problem that you will face is that these phones were designed to use nickel cadmium (NiCd) batteries, which are obsolete so expensive and difficult to source. If you fit modern nickel metal hydride (NiMH) batteries, they won't charge properly and will have a short life.
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#3 |
Nonode
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 2,057
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NICAD cells are difficult to source as you say, but as the voltage is 1.2, might be worth using 1.2v NIMH cells, which are available ,or is this option a nun runner. Few places on net selling 1.2NIMH, and I'm certain I've spotted 1.2v NIMH in the likes of Poundland /possibly also Aldi . Can't really be certain as i was looking for 1.5v rechargeables to fit remotes designed for dry cells.
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#4 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,538
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NiMH won't charge properly if the charging circuit is designed for NiCd.
Àll NiCd and NiMH cells are 1.2V nominal, though the actual voltage will depend on the charge state. |
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#5 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 16,137
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These were made by Uniden.
There’s a hidden screw under the number label ![]() |
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#6 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 5,618
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Yes, I discovered the charging problem with NiMH cells in my Rabbit telephones. They simply didn't charge using the base station intended for NiCd cells.
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Mending is better than Ending (cf Brave New World by Aldous Huxley) |
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#7 | |
Dekatron
Join Date: May 2010
Location: Manchester, UK.
Posts: 3,241
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The only consumer 1.5v rechargeable cells I know of were branded "Pure Energy" and were rechargeable alkaline. They were chosen for one particular application (a domestic energy usage monitor sponsored by Southern Electric and others) because of their perceived "green" credentials (contained no heavy metals) but scored an own goal by leaking and sending the power monitors to WEEE in record time
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-- Graham. G3ZVT Last edited by rambo1152; 5th Mar 2022 at 12:31 am. |
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#8 | |
Diode
Join Date: Oct 2021
Location: Plymouth, Devon, UK.
Posts: 6
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Thanks to those also who have provide information about the charging problems with Ni-MH batteries. The 3 cell Ni-Cd batteries seem to be available online, but as the Mod says these are expensive at £25. I guess not worth trying the Ni-MH cells? |
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#9 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,538
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No reason not to try NiMH cells, but you should expect them to have a short life. Don't leave a charged phone on the charging cradle if you can avoid it. The Poundland cheapies may be worth a punt despite their relatively low capacity.
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#10 |
Dekatron
Join Date: May 2010
Location: Manchester, UK.
Posts: 3,241
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Also don't discuss anything remotely confidential using this phone.
Along with baby monitors, it's trivial to eavesdrop on these early cordless phones.
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-- Graham. G3ZVT |
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#11 |
Diode
Join Date: Oct 2021
Location: Plymouth, Devon, UK.
Posts: 6
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Thanks to all those who have replied with the very helpful information, I've learnt a lot. Having got the phone apart, there is a bit of soldering work to be done where the leads have come apart around the old battery before I can install a new battery.
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#12 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 3,207
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-Why the issue with NiMH in a NiCad 'phone...? Does the charging circuit seek to detect the slight volt drop of a NiCad when reaching full charge?
Dave |
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#13 |
Octode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 1,739
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#14 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 4,668
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Interesting. The Jessops own brand plug-in AA/AAA chargers I bought in the 1990's are stated to be suitable for both Ni-Cd and Ni-MH batteries. They were supplied with Ni-CD AA cells. I used to use them (infrequently) for charging the Ni-MH AA replacements I use in my original digital camera without problems, but now use a Panasonic charger that is specified to be for Ni-MH cells.
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#15 | |
Octode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 1,739
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Last edited by duncanlowe; 3rd May 2022 at 7:44 am. |
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#16 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 16,137
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These phones date from the mid-1980s, and I always thought that the charging was simply a slow trickle charge.
I used to have a circuit diagram, but I'm afraid I got rid of it as I thought these phones had been extinct for about 25-30 years! Good luck with getting yours working. They're good fun and seemed amazing when they were current if all you were used to was a 746 tied to a table in the hall. I think they were the first BABT approved cordless phone, the others that you sometimes saw around being non-approved grey imports (ISTR Del Boy had one!). They were made by Uniden but rebranded as BT, Tandy and others. My late grandfather picked one up at a jumble sale for me when they were still current, and all that was required to get it going was a replacement battery pack. Happy days! Last edited by Nickthedentist; 3rd May 2022 at 9:13 am. |
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#17 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 16,137
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Maybe this is what you need, but I dread to think what the cost might be nowadays:
https://int.rsdelivers.com/product/r...k-pack/2042761 |
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#18 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 4,644
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£17 plus VAT
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Kevin |
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