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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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15th Nov 2022, 2:44 pm | #1 |
Diode
Join Date: Nov 2022
Location: Plymouth, Devon, UK.
Posts: 5
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Murphy B40 C
First time posting , I have dug out my Dads Murphy B40 C , complete except the mains lead , after a bit of searching found a plessey mk 4 , 3 pin plug , however found it wouldn't fit the B40 without the appropriate 3 pin socket .
Does any one know where I could find a connecting socket , would love to try and get it going , Rob |
15th Nov 2022, 3:46 pm | #2 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: Murphy B40 C
Welcome Rob.
First things first, do you have the necessary electronics knowledge to tackle this? What level of electronics experience do you have? It's not the end of the world if you're wanting in this department, but we need to know so as to pitch any help at the right level. For now, do not switch the set on (when you locate that lead), as things need to be checked first otherwise you may cause irreparable damage. That's unlikely, but quite possible. Best of luck.
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15th Nov 2022, 4:02 pm | #3 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
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Re: Murphy B40 C
Welcome Rob to the forum. Loads of info on the web site and as stated do not just plug in
. There certain components that need checking/changing etc.
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15th Nov 2022, 4:18 pm | #4 |
Octode
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,573
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Re: Murphy B40 C
Welcome Rob to the forum.
B40 what a heavy set. Had one many years ago when I could move it. One question not asked of you is do you know the history of the radio? When was your dad last using it, was it regularly in use, had any work been done on it by your father etc. The reason for the caution is that capacitors in vintage radios can, and do go electrically leaky, as such when mains is applied and the HT is present within the set, these capacitors draw cuurent all the time, they can get hot and even cause damage to other components such as internal transformers and valves. Good luck. Adrian |
16th Nov 2022, 9:57 am | #5 |
Diode
Join Date: Nov 2022
Location: Plymouth, Devon, UK.
Posts: 5
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Re: Murphy B40 C
Thank you one and all for your replies ! . I certainly won't just switch on when I have located the part . It hasn't been used for 20 years , before that my Dad used it regularly . He was in the Navy and said if you can get it going I can certainly show you how to use it . A lot more research required I think , going to enjoy it ! , Thank you again , Rob
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19th Nov 2022, 10:59 pm | #6 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Murphy B40 C
Quote:
Also bear in mind what everyone else has said about knowiing what you are doing ***before*** you switch it on. Not observing this could result in serious tears....... Richard |
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19th Nov 2022, 11:06 pm | #7 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Murphy B40 C
'Socket on the receiver', i.e. a plug on the receiver end of the mains lead? Are you sure, that sounds somewhat dangerous!
Andy |
19th Nov 2022, 11:16 pm | #8 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Murphy B40 C
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19th Nov 2022, 11:23 pm | #9 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,398
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Re: Murphy B40 C
It's entirely possible that I'm misinterpreting here, but I get the impression that Rob has a mains lead with 3-pole Plessey Mk4 connector, but needs one that will mate with the 2-pole + shell earth Plessey Mk4 fitted as standard to the B40 PSU- though the latter may have been fitted with something else over its several decades.
Colin |
20th Nov 2022, 12:26 am | #10 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Murphy B40 C
Colin,
yes, I can see we are all struggling to understand exactly what has been done here. Some photos will be essential to make progress with this one. Richard |
20th Nov 2022, 11:43 am | #11 |
Diode
Join Date: Nov 2022
Location: Plymouth, Devon, UK.
Posts: 5
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Re: Murphy B40 C
What a fantastic forum/community, yes pictures coming soon. I'm looking out for a sturdy table at the moment, so I can get it at a decent height to work on in my Dad's conservatory, what a weight that thing is.
Because of the nature of my work I am very busy November and December but have plenty of spare time January and February, I have downloaded the manual and I do have electrical test equipment. However because this completely new to me my naivety will become apparent, apologies in advance, Rob |
20th Nov 2022, 1:00 pm | #12 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Murphy B40 C
Richard,
Sorry, but 'female plug' and 'male socket' are oxymorons, resulting in ambiguity. My definitions of 'plug' and 'socket' come from an entire career in the aircraft industry, where confusion can be both costly and time-wasting (which of course is also costly), with connectors costing hundreds of pounds and many weeks lead time. A plug has male contacts, and a socket has female contacts. Simple! It doesn't matter whether the item is mounted on the end of a cable or chassis-mounted, this is a different attribute which must also be specified. So we can have a free (cable-mounted) plug or socket, and a fixed (chassis-mounted) plug or socket. Of course there are odd-ball connectors which don't match this rule, such as hermaphrodite coax connectors, and others with a mix of male and female pins I have sen described as a 'plocket'! But for straightforward connectors such as Plessey Mk4 the correct terminolgy is simple. Andy |
20th Nov 2022, 1:23 pm | #13 |
Pentode
Join Date: Sep 2007
Location: Fareham, Hampshire, UK.
Posts: 104
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Re: Murphy B40 C
The very first B40 series receivers had W connectors for the mains inputs, but all later sets from the B40A on-wards had a 2 pin Plessey Mk4 plug. The earth connection was a stud near the headphone sockets presumably to avoid earth loops!
Many have been modified to use a 3 pin Plessey Mk4. Others have a 3 pin miniature Bulgin circular connector as fitted to much Marconi instruments kit etc. |
20th Nov 2022, 4:31 pm | #14 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Murphy B40 C
Quote:
Richard |
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20th Nov 2022, 4:36 pm | #15 | ||
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,833
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Re: Murphy B40 C
Quote:
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20th Nov 2022, 6:39 pm | #16 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Murphy B40 C
The bit with the male pins was called a plug in an early Bulgin catalogue.
The last Murphy B40D I owned was fitted with a 3 pin Bulgin chassis plug. Photo of receiver as received. Lawrence. Last edited by ms660; 20th Nov 2022 at 6:53 pm. Reason: extra info |
20th Nov 2022, 10:29 pm | #17 |
Nonode
Join Date: Jun 2010
Location: Spalding, Peterborough, Cambridgeshire, UK.
Posts: 2,859
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Re: Murphy B40 C
Plug or socket on the mains cable. If a Plessey mk4, it can carefully be dismantled and the black insert containing the 3 contacts rotated to align correctly with the B40 one.
CHECK CAREFULLY THE RESULTING CONNECTIONS! A bit fiddly, sometimes parts are reluctant to part, but it is possible with patience and care plus maybe a little elbow grease! (another) Rob
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20th Nov 2022, 11:15 pm | #18 | |
Tetrode
Join Date: Apr 2021
Location: North Surrey, UK.
Posts: 67
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Re: Murphy B40 C
Quote:
In the army (and presumably followed as a standard in the other services): EMER Workshops F100 Section 123 paragraph 10: "The insert is moulded to carry the contacts which may be pins, and the jnsert is then termed a PLUG. If the contacts are in tube form the insert is termed a SOCKET. A plug or socket insert may be fitted to either a free or fixed shell." B40A to B40C receivers were always fitted with 2-pin fixed plugs for the mains supply in Navy service with a separate earth connection. A B40 with a 3-pin plug will have been modified in later life. Last edited by 2000 type; 20th Nov 2022 at 11:26 pm. |
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20th Nov 2022, 11:40 pm | #19 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Murphy B40 C
Attached is a page from a document entitled 'Plugs and Sockets' issued by the Ministry of Aircraft Production in 1942.
Paragraphs 6a) and b) define a Plug and a Socket. andy |
22nd Nov 2022, 11:40 pm | #20 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: Murphy B40 C
So.... your mains extension leads have plugs on each end do they?
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