Eddystone EC10. - UK Vintage Radio Repair and Restoration Discussion Forum

See_Mos · 25th Jun 2025, 10:08 pm

Ok, so I bought an EC10 MK 1 that was for sale on eBay.

It was described as spares or repair so I was taking a big risk but as it happens it is not too bad. The knobs are all wrong, the battery holder is missing, it has been ‘got at’ and it is generally quite grubby and greasy inside.

After a few basic checks there was nothing major to worry about so I powered it from my bench supply with the current limit at 500mA. I turned the AGC off and the RF gain full up and starting on MW just a couple of very weak distorted stations. After much prattling about I discovered that the set went into violent oscillation if the RF gain was set too high. Turn it down and the set is working somewhat.

The cause is an incorrect potentiometer, it is 22K log instead of 10K and the volumes control has also been changed for something which originally had a switch on the back so I will order new ones.

I assume the 5K volume will be the usual log type but what about the RF gain, should it be a log or linear type? I suspect linear.

HamishBoxer · 26th Jun 2025, 7:46 am

Check the AF117s for "whiskers". You can as a temporary cure, snip off the shield lead on the AFs.

See_Mos · 26th Jun 2025, 8:49 am

I did expect to find problems with whiskers having repaired hundreds of trannies which have had the same problem but only one has the fault and a previous owner already left the screen wire floating. The final I.F. And BFO have been replaced with AF124 by a previous owner. I had already decided to replace the OC171’s with AF12x series even before the set arrived.

The set is working but not as well as it might but before I get into mods or realignment I want to sort out and tidy up previous repairs.

HamishBoxer · 26th Jun 2025, 10:25 am

Sounds a very sensible approach to fault finding, nothing worse than man made faults if been got at.

G6Tanuki · 27th Jun 2025, 2:14 pm

The EC10 is an interesting example of a first generation transistor HF receiver, with a range of pros and cons. Yes, it has an Eddystone silky smooth tuning drive, but the tuning rate is horrendous, specially if trying to resolve SSB stations. Similarly the IF selectivity may be OK for AM broadcast reception but is about 10KHz too much for SSB. And the low IF means images galore above 10MHz. At least solid statery means a lot less thermal drift than was evident in similar era single conversion valve receivers.

Think of it as being "of its time", and accept its foibles as well as enjoying sorting out the previous owners' efforts!!

I had one in the early 70s, used as the tunable IF for a couple of crystal controlled VHF converters. Was amazed to see one on offer for well over £100 at the recent Farrington Gurney rally.

dave walsh · 28th Jun 2025, 10:03 am

I was a teenager when this model came out in 1963. The EC10 seemed to be very modern and interesting in it's looks, small size and transistor circuitry It was very expensive then as I recall but I didn't feel envious as I was expecting it to have a communications RX basis for the money

[ I wouldn't have had anything like the price of course anyway]. It was promoted as a SW set but as indicated, it was fairly basic.

I have noticed, over the years, though, that they have remained sought after and I've seen them sold at Rallies where the new owners seemed delighted with their "bargains". I think there is a comparison with the war time classic valve Utility Sets. They still seem to hold their price very well, as a smalll and very basic "woodie". I suspect that some owners may have wanted the Eddystone set for appearance and suitability in a domestic setting eg as a handy bedside set perhaps

Another comparator may be with the antiques trade where smaller items often sell better as witnessed in the many TV/Auction programs, often watched by members here! No EC10's yet as far as I know!

Dave W

See_Mos · 30th Jun 2025, 10:51 am

OK, I cleaned most of the muck from the RF PCB and underneath is a fibre glass board. My first thoughts were that this might have been a prototype but more likely a previous owner has made his own board. If that is the case then it has been reasonably well done except for the left corner at junction of B-, R31 and an electrolytic which I think might be C81.

The resistors on both boards are a strange mix of carbon, metal film and those horrible blue-grey ones that I think were made by Phillips. The soldering on the IF/audio board looks original but the variety of resistors reminds me of back in the 70's when I bought a big box with over a thousand surplus mixed resistors for very little money. Many of the resistors types and values are the same as in that box.

The co-ax from the RF board to the IF looks to be audio quality. Apart from detuning the first IF I am not sure if it will make much difference but unfortunately I don't have a piece of small RF or video co-ax long enough to replace it.

The photo of the RF board still has some of the muck next to the tuning capacitor, though here it was not nearly as bad as the rest. Strangely the IF/audio board is fairly clean.

As I wrote previously it does work and having checked, but not yet touched, the alignment using my DDS generator the alignment is pretty close to what it should be so considering what I paid for the set then I cannot complain.

Radio Wrangler · 30th Jun 2025, 12:58 pm

If you look at an EC10 as basically a run of the mill germanium transistor broadcast portable, fitted with a coil pack extended to shortwave bands, planted in a nice case with a much better dial/drive - you won't go far wrong.

You'll also then find the prices they still fetch staggering.

Certainly they look *very* cute, but the FRG7 and several generations of the little Lowe receivers are much more satisfactory if you intend to use it as more than a shelf ornament.

David

dave walsh · 30th Jun 2025, 1:56 pm

Very well summarised there David. I 'm very interested in watching your progress See Mos, despite never having been up to "solid state" devices [or much else] myself.

From your description, it doesn't sound like the case itself is damaged, so whether you can "tweak" it electronically or not you won't have taken much of a risk in the first place and could end up with an item of value whether that's money or otherwise!

Dave Walsh
Bexhill

David G4EBT · 30th Jun 2025, 7:19 pm

For anyone who might not know, there's a raft of information on the whole range of Eddystone equipment at the Eddystone User Group website, freely accessible to any Eddystone enthusiasts:

https://eddystoneusergroup.org.uk

Scores of restorations stories including quite a few on the EC10 MK1 & Mk2, such as a stabilised mains power supply for the EC10 by Stef Niewiadomski (Forum member 'Sadddlestone Man').

https://eddystoneusergroup.org.uk/restoration-projects/

And scans of many service manuals and owner manuals here:

https://eddystoneusergroup.org.uk/service-manuals-for-eddystone-receivers/

Hope that might be of interest.

See_Mos · 5th Jul 2025, 4:31 pm

Oh dear, now I have a problem!

But before I get to that I am puzzled by the difference in amplitude and wave shape of the local oscillator between bands. At the emitter of TR2 there is 2v P-P on most ranges but 6v P-P and distorted on range 3. Also even without an aerial of any sorts there are a lot of FM radio stations breaking through on band 18-30MHz band but no AM stations at all.

While investigating the problem one of the waveband switch wafers that had previously been repaired with Araldite came apart as I was pushing my scope probe to get to a resistor. I will try to repair it but I think it will be problematic. There are similar looking wafers on Ebay but I will need the exact part to match the other wafers which are 2 pole 5 way and 3 pole 5 way. I could do a complete rebuild but the old RS switch parts would not line up with the front panel markings and the prices on Ebay are crazy. It would be cheaper to buy another set.

Has anyone got a scrapper please?

25th Jun 2025, 10:08 pm	#1
See_Mos Heptode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 655	Eddystone EC10. Ok, so I bought an EC10 MK 1 that was for sale on eBay. It was described as spares or repair so I was taking a big risk but as it happens it is not too bad. The knobs are all wrong, the battery holder is missing, it has been ‘got at’ and it is generally quite grubby and greasy inside. After a few basic checks there was nothing major to worry about so I powered it from my bench supply with the current limit at 500mA. I turned the AGC off and the RF gain full up and starting on MW just a couple of very weak distorted stations. After much prattling about I discovered that the set went into violent oscillation if the RF gain was set too high. Turn it down and the set is working somewhat. The cause is an incorrect potentiometer, it is 22K log instead of 10K and the volumes control has also been changed for something which originally had a switch on the back so I will order new ones. I assume the 5K volume will be the usual log type but what about the RF gain, should it be a log or linear type? I suspect linear.

26th Jun 2025, 7:46 am	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 9,178	Re: Eddystone EC10. Check the AF117s for "whiskers". You can as a temporary cure, snip off the shield lead on the AFs. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

26th Jun 2025, 8:49 am	#3
See_Mos Heptode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 655	Re: Eddystone EC10. I did expect to find problems with whiskers having repaired hundreds of trannies which have had the same problem but only one has the fault and a previous owner already left the screen wire floating. The final I.F. And BFO have been replaced with AF124 by a previous owner. I had already decided to replace the OC171’s with AF12x series even before the set arrived. The set is working but not as well as it might but before I get into mods or realignment I want to sort out and tidy up previous repairs.

26th Jun 2025, 10:25 am	#4
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 9,178	Re: Eddystone EC10. Sounds a very sensible approach to fault finding, nothing worse than man made faults if been got at. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

27th Jun 2025, 2:14 pm	#5
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 15,760	Re: Eddystone EC10. The EC10 is an interesting example of a first generation transistor HF receiver, with a range of pros and cons. Yes, it has an Eddystone silky smooth tuning drive, but the tuning rate is horrendous, specially if trying to resolve SSB stations. Similarly the IF selectivity may be OK for AM broadcast reception but is about 10KHz too much for SSB. And the low IF means images galore above 10MHz. At least solid statery means a lot less thermal drift than was evident in similar era single conversion valve receivers. Think of it as being "of its time", and accept its foibles as well as enjoying sorting out the previous owners' efforts!! I had one in the early 70s, used as the tunable IF for a couple of crystal controlled VHF converters. Was amazed to see one on offer for well over £100 at the recent Farrington Gurney rally. __________________ "It's not true that I had nothing on. I had the radio on!" -Marilyn Monroe .

28th Jun 2025, 10:03 am	#6
dave walsh Dekatron Join Date: Jan 2006 Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex. Posts: 6,037	Re: Eddystone EC10. I was a teenager when this model came out in 1963. The EC10 seemed to be very modern and interesting in it's looks, small size and transistor circuitry It was very expensive then as I recall but I didn't feel envious as I was expecting it to have a communications RX basis for the money [ I wouldn't have had anything like the price of course anyway]. It was promoted as a SW set but as indicated, it was fairly basic. I have noticed, over the years, though, that they have remained sought after and I've seen them sold at Rallies where the new owners seemed delighted with their "bargains". I think there is a comparison with the war time classic valve Utility Sets. They still seem to hold their price very well, as a smalll and very basic "woodie". I suspect that some owners may have wanted the Eddystone set for appearance and suitability in a domestic setting eg as a handy bedside set perhaps Another comparator may be with the antiques trade where smaller items often sell better as witnessed in the many TV/Auction programs, often watched by members here! No EC10's yet as far as I know! Dave W Last edited by dave walsh; 28th Jun 2025 at 10:08 am.

30th Jun 2025, 10:51 am	#7
See_Mos Heptode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 655	Re: Eddystone EC10. OK, I cleaned most of the muck from the RF PCB and underneath is a fibre glass board. My first thoughts were that this might have been a prototype but more likely a previous owner has made his own board. If that is the case then it has been reasonably well done except for the left corner at junction of B-, R31 and an electrolytic which I think might be C81. The resistors on both boards are a strange mix of carbon, metal film and those horrible blue-grey ones that I think were made by Phillips. The soldering on the IF/audio board looks original but the variety of resistors reminds me of back in the 70's when I bought a big box with over a thousand surplus mixed resistors for very little money. Many of the resistors types and values are the same as in that box. The co-ax from the RF board to the IF looks to be audio quality. Apart from detuning the first IF I am not sure if it will make much difference but unfortunately I don't have a piece of small RF or video co-ax long enough to replace it. The photo of the RF board still has some of the muck next to the tuning capacitor, though here it was not nearly as bad as the rest. Strangely the IF/audio board is fairly clean. As I wrote previously it does work and having checked, but not yet touched, the alignment using my DDS generator the alignment is pretty close to what it should be so considering what I paid for the set then I cannot complain. Attached Thumbnails

30th Jun 2025, 12:58 pm	#8
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 24,748	Re: Eddystone EC10. If you look at an EC10 as basically a run of the mill germanium transistor broadcast portable, fitted with a coil pack extended to shortwave bands, planted in a nice case with a much better dial/drive - you won't go far wrong. You'll also then find the prices they still fetch staggering. Certainly they look very cute, but the FRG7 and several generations of the little Lowe receivers are much more satisfactory if you intend to use it as more than a shelf ornament. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

30th Jun 2025, 1:56 pm	#9
dave walsh Dekatron Join Date: Jan 2006 Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex. Posts: 6,037	Re: Eddystone EC10. Very well summarised there David. I 'm very interested in watching your progress See Mos, despite never having been up to "solid state" devices [or much else] myself. From your description, it doesn't sound like the case itself is damaged, so whether you can "tweak" it electronically or not you won't have taken much of a risk in the first place and could end up with an item of value whether that's money or otherwise! Dave Walsh Bexhill

30th Jun 2025, 7:19 pm	#10
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 6,176	Re: Eddystone EC10. For anyone who might not know, there's a raft of information on the whole range of Eddystone equipment at the Eddystone User Group website, freely accessible to any Eddystone enthusiasts: https://eddystoneusergroup.org.uk Scores of restorations stories including quite a few on the EC10 MK1 & Mk2, such as a stabilised mains power supply for the EC10 by Stef Niewiadomski (Forum member 'Sadddlestone Man'). https://eddystoneusergroup.org.uk/restoration-projects/ And scans of many service manuals and owner manuals here: https://eddystoneusergroup.org.uk/service-manuals-for-eddystone-receivers/ Hope that might be of interest. __________________ David. BVWS Member. G-QRP Club member 1339. Last edited by David G4EBT; 30th Jun 2025 at 7:19 pm. Reason: typo

5th Jul 2025, 4:31 pm	#11
See_Mos Heptode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 655	Re: Eddystone EC10. Oh dear, now I have a problem! But before I get to that I am puzzled by the difference in amplitude and wave shape of the local oscillator between bands. At the emitter of TR2 there is 2v P-P on most ranges but 6v P-P and distorted on range 3. Also even without an aerial of any sorts there are a lot of FM radio stations breaking through on band 18-30MHz band but no AM stations at all. While investigating the problem one of the waveband switch wafers that had previously been repaired with Araldite came apart as I was pushing my scope probe to get to a resistor. I will try to repair it but I think it will be problematic. There are similar looking wafers on Ebay but I will need the exact part to match the other wafers which are 2 pole 5 way and 3 pole 5 way. I could do a complete rebuild but the old RS switch parts would not line up with the front panel markings and the prices on Ebay are crazy. It would be cheaper to buy another set. Has anyone got a scrapper please?