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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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12th Apr 2018, 8:09 pm | #1 |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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New Member and need to identify a set (Jonell A50)
Hi all,
Thanks for letting me in. I have just picked up a set and am coming across a wall of nothing on the internet regarding schematic or even model number. The set is branded Jonell and is a full Mains only AC set judging by the transformer and the 6X5 rectifier valve. I did discover online that Jonell was a John Lewis own brand but the sets were made by someone else. If I can find that 'someone else' I may have a chance of restoring this thing without having to work blind. On the back there is a plate with NYO1974 but there is also the imprint in reverse of a serial number. I am wondering if I remove this plate if the model details will be revealed, but at this stage I haven't taken any tools anywhere near it, let alone drilled out a rivet or two! Attached are some pictures which might be instantly recognisable to someone as well as a quick layout sketch with the valve designations on it. Hope someone can help. George |
12th Apr 2018, 9:52 pm | #2 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: New Member and need to identify a set.
EF39 sounds wrong in that lineup, though it will likely work. 6K7G would be more likely. Is the output a 6V6GT?
The circuit will be pretty much defined by the valve lineup- just find a circuit for another set with the same valves as a starting point, details like slightly different R and C values can be filled in from the actual parts fitted in the set. With a bit of luck, you won't need to delve into the mysteries of the front end coilpack other than perhaps to clean the wavechange switch contacts. Something like this: https://www.radiomuseum.org/r/master..._d154d_15.html might be a good start.
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12th Apr 2018, 10:00 pm | #3 |
Moderator
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Location: Exeter, Devon and Poole, Dorset UK.
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Re: New Member and need to identify a set.
This seems to have a lot in common with this set
https://www.radiomuseum.org/r/ace_a51a_5.html A lot of these sets turned up with different names a lot of them were were built by companies like Plessey. Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
13th Apr 2018, 1:42 am | #4 | |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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I'm not sure of the type of valve between the 6Q7 and the 6X5. It's the only one with no markings on it. I'm not sure that any of the valves are in the right positions or even if they should be there at all. This was a first look situation. It's one of two that arrived today, the other being a Bush VHF81. That one was less intriguing to me so it's the reason I have started with this set first. Quite surprised to have hit a blank wall so early but all is not lost. If anything, this will actually make me think more about the functions of each part rather than just a works= OK, broken=change it situation. Been a long time since going that deep and I'm no more than a valve beginner in some respects. Simple amps no problem, but things that are meant to oscillate? Preposterous!!!
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13th Apr 2018, 10:07 am | #5 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,766
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Re: New Member and need to identify a set.
Did a say something wrong! all I said was you don't need a circuit it's a basic set , this is a good way to learn the in's and outs of radio repair , with help from all here on the forum . Mick.
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13th Apr 2018, 10:17 am | #6 |
Moderator
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Re: New Member and need to identify a set.
I don't know what you're implying, but no posts have been deleted from this thread.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
13th Apr 2018, 10:33 am | #7 |
Rest in Peace
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Location: Ripley, Derbyshire, UK.
Posts: 785
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Re: New Member and need to identify a set.
Hi George,
At first glance it looks like a typical 50s line-up, except for the EF39 which has probably been fitted at some time to replace a faulty 6K7. One thing I notice is the small size of the mains transformer, which suggests it could be basically a low-voltage transformer to supply the valve heaters. If this is the case, the chassis will have a connection directly to the mains, as in an AC/DC set. I advise caution in your testing and repair. Ensure the power connection is such that the neutral side of the mains goes to the chassis, or an isolatoin transformer is used to prevent the chassis becoming "live", the consequences of which could be unpleasant/fatal. The transformer may be a fully isolating one, but I respectfully suggest you check on this before starting work on the set. Tony. |
13th Apr 2018, 10:40 am | #8 |
Retired Dormant Member
Join Date: Jan 2018
Location: Chamalières, France.
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Re: New Member and need to identify a set.
In respect to the final audio valve, sometimes the impedance Z is marked on the audio transformer. So around 7000, the valve is 6F6, if 5000 it's a 6V6. Also the anode shape of the 6F6 is quite perfect cylindric, meanwhile the 6V6 is not.
regards, Roger |
13th Apr 2018, 11:29 am | #9 |
Pentode
Join Date: Oct 2010
Location: Banff, Aberdeenshire, UK.
Posts: 104
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Re: New Member and need to identify a set.
George,
I have an identical set, and years ago (something like fifteen I think) I wrote a piece about them that was published in the BVWS magazine. Not sure I still have a copy? The sets were indeed made for and sold by the John Lewis Partnership's stores. I used to work for that company and in the 1980s the company archivist kindly dug out various bits of information for me. As has already been correctly surmised by others, JLP had a deal with Ace Radios for supply, and my memory is their A50 model was the basis (but the A51 could easily be true instead). I have an A50 somewhere in the back of a cupboard! JLP aimed these sets as being sold on an in-house HP scheme, and I expect that made as much money for the company as the radio itself. If you go to a JLP store today you will see that the in-house brand is Jonelle, with an extra 'e' on the end. The spelling changed from Jonell to Jonelle gradually during the 1950s and 60s, and I was told the reason was the large ranges of ladies clothing and fashion accessories sold under the brand name seemed more French, exotic and feminine with the extra 'e' added! best wishes Duncan |
13th Apr 2018, 12:00 pm | #10 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,766
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Re: New Member and need to identify a set.
Hi George do you have a test meter , if so check if you have a reading to chassis from both sides of the mains lead, set switched on , meter on the ohms range .I was thinking on the same lines as Tony regarding the mains transformer .Mick.
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13th Apr 2018, 12:19 pm | #11 |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
No, nothing wrong said. I agree with you and as you say, with the help of the forum, and my dry and dusty brain, I should be able to get things going again. I'm actually looking forward to getting in there and seeing how much or how little work will be needed.
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13th Apr 2018, 12:25 pm | #12 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: New Member and need to identify a set.
25L6GT output valve?
Lawrence. |
13th Apr 2018, 12:26 pm | #13 | ||
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
Quote:
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Scratch that. Just got the valve out and under a magnifying light. I can just see the remains of 6V6GT in the glass. The base is marked Hytron Bantam with 11 over the number 9. Thanks for your input. |
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13th Apr 2018, 12:41 pm | #14 |
Moderator
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Re: New Member and need to identify a set.
Duncans article can be viewed here
https://www.bvws.org.uk/publications...letin_28_4.pdf Starts on Page 24 Nice article it is too Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
13th Apr 2018, 12:47 pm | #15 | |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
Quote:
I have a reasonably equipped bench and will be looking at all of the set from a safety point of view. I think the order in which I will go at this set is to first decab it, then photograph everything as is so I can at least remember where everything is as it was. After that it will be a case of metering everything out, testing components and generally assessing everything. |
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13th Apr 2018, 1:45 pm | #16 |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
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13th Apr 2018, 3:58 pm | #17 |
Pentode
Join Date: Oct 2010
Location: Banff, Aberdeenshire, UK.
Posts: 104
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Re: New Member and need to identify a set.
Gosh Mike.....thanks for finding that article. I hadn't seen it since it was published and that was indeed fifteen years ago. Must be about time I wrote something else for BVWS!
best wishes Duncan |
13th Apr 2018, 10:15 pm | #18 |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
I finally got the diagrams from radiomuseum and electrically they are fairly similar. The pictures there show similarities to both the A50 and the A51, being a cross between the two. It has the speaker grille of the A51 as well as the knob layout but the dial style of the A50. Either way, I'm going to take a lot of pictures and video, take it out of the case and then assess what needs to be done. This will certainly involve more video and picture taking before I even get the fluke on it. If I really feel old school I could use my Avo8...
I will then have to do a lot of thinking. Is this going to be a brush up and polish or a full restore? I would like to do a full restore but I am not sure my non electronic skills are up to the job. Just rebuilding it with new components is a walk in the park but I think the set deserves a bit more care than just that. Looks like i'll be spending time in the restoring parts of the board to help me decide. Many thanks to all those who have commented so far. No doubt I'll be popping in asking silly questions from time to time. |
14th Apr 2018, 5:16 am | #19 |
Triode
Join Date: Apr 2018
Location: Northampton, Northamptonshire, UK.
Posts: 41
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Re: New Member and need to identify a set.
Another update! It is definitely an A50. After taking it out of the cabinet and looking through the wiring it pretty well matches the A50 diagram that I have. The transformer at the front is a full HT+Heater unit and the one I thought was the output transformer is actually a choke. The real output transformer is underneath the chassis.
The wiring is a mix of cloth and plastic/rubber covered and it doesn't look very good. I would say that there has been some resoldering going on. The switches look to be in pretty good condition, unlike all the electrolytic caps which are only fit for disposal. I did find a date on the main filter capacitor of September 1949 so it puts it two years before the A51 set but a later production A50. The main tuning capacitor is dirty and shows some oxidisation on it as well as rust on the steel part. The rubber supports for it though are still soft to the touch. Valves look ok but I will test them before firing it up (a long way off from that yet) but the grid caps and wiring on all of them are in poor condition. Sockets are all tight and riveted in with aluminium blind rivets. Controls feel ok, but need cleaning and lubricating as well as testing. Dial pointer is bent slightly but not actually damaged as such. The chassis itself as well as the tops of the transformers are all coated in a layer of rust. It looks nasty so I am actually tempted to do a complete strip down of the top side of the chassis and not so much as start from scratch but deep clean the surface. I have taken a lot of photographs and also shot a reasonable amount of video which will probably end up on my YouTube channel but I was wondering if protocol here allowed for a build gallery of pictures on a start to finish basis. I will have to convert all the pictures first anyway as they are in Nikon raw format and some will be duplicates as I tend to overshoot and delete. Thank god for digital cameras, I couldn't afford to do it with 35mm film. As before, Many thanks to those who have commented and given me suggestions as to where to start. Your help is much appreciated. Best Wishes to all. George |
15th Apr 2018, 1:03 pm | #20 |
Octode
Join Date: Jun 2005
Location: Sheffield, South Yorkshire, UK.
Posts: 1,227
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Re: New Member and need to identify a set (Jonell)
I have one of these but not near it at the moment . I remember it being similar to AceA50 and used the circuit for it. The Jonell is using less components and probably could be improved. I do remember 6K7 and 6V6.
There was not much wrong with it but very weak without a good external aerial . Mine had no back on it so I improvised one.the original thread might still be on here,from 2007. |