UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Closed Thread
 
Thread Tools
Old 2nd Nov 2014, 11:21 am   #1
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Ekco A22 Advice

I was recently (very kindly) given an Ekco A22 which has been in my partner's family from new. It has never been restored and, other than servicing during it's early life, has never had any fettling whatsoever and has only ever been stored in a heated home environment. As such, it's in quite remarkably good nick.

Apparently it has not been run in perhaps more than 20 years so nobody really knows whether it is in working order. When I have a bit more time, I'll give it a thorough inspection followed by gentle power up via a lamp limiter. However, given the condition of this set, are there any other precautions I should take before applying power? I really don't want to inadvertently do anything which might cause unnecessary damage to such a gorgeous set.
Attached Thumbnails
Click image for larger version

Name:	a22_DSC5408.jpg
Views:	447
Size:	46.4 KB
ID:	99599   Click image for larger version

Name:	a22_DSC5410.jpg
Views:	567
Size:	55.3 KB
ID:	99600   Click image for larger version

Name:	a22_DSC5411.jpg
Views:	526
Size:	77.1 KB
ID:	99601  
PSValves is offline  
Old 2nd Nov 2014, 12:38 pm   #2
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 13,168
Default Re: Ekco A22 Advice

Congratulations

Well there's no "that" capacitor to worry about since it's a short set. The tone corrector is across the O/P TX primary so that can't damage anything. I'd check the output valve cathode bias resistor and decoupling cap plus the main smoothing caps and if they look OK, give it a go on the lamp. Careful measurements should then show up any other nasties without much risk of damage.

If it requires work, it's then up to you to decide how original you want it to be/look or whether just to keep it as an original display piece.
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline  
Old 2nd Nov 2014, 1:59 pm   #3
Stuart R
Hexode
 
Stuart R's Avatar
 
Join Date: May 2011
Location: Letchworth Garden City, Hertfordshire, UK.
Posts: 377
Default Re: Ekco A22 Advice

If you delve deeper, be careful when unscrewing the chassis.

I used a flared screwdriver and the wide part managed to clip one of the SW trimmers by the bottom right-hand screw.

Result is a snapped piece of brass on the trimmer and no SW reception.



Mr Clumsy.
Stuart R is offline  
Old 2nd Nov 2014, 3:00 pm   #4
andycapp
Rest in Peace
 
Join Date: Aug 2014
Location: Bath, Avon, UK
Posts: 235
Default Re: Ekco A22 Advice

What a gorgeous set and what a lucky man. Andy
andycapp is offline  
Old 2nd Nov 2014, 6:43 pm   #5
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 3,549
Default Re: Ekco A22 Advice

I'd be very cautious about operating this set without a very careful examination, which will most likely reveal that it needs to undergo considerable restoration work, which I'll outline.

I've restored three A22s - one for myself - two for one of my sons. In each case, most of the rubber insulated wiring had perished and become brittle, including that in the wiring loom around the chassis, which contains both high and low voltage wires running alongside each other. In each case, I made up a new wiring loom using heat resistant silicone rubber insulated flex (obtainable in a range of vintage colours from forum member Phil Marrison 'SWB 18'). Also, the wiring to the dial bulb in the tuning wand had perished, and as the tuning wand is swung around the dial, the leads to the dial bulb are constantly flexed.

If the set draws excess current, as it may well do due to leaky capacitors, the mains transformer is quite small and only really up to the task. The smoothing choke is quite small too. In two of the sets I restored, the mains transformers had burnt out - no doubt because of excess current due to leaky capacitors (in the electrical sense), which can also damage the output transformer and the rare and expensive EBL31 output valve. Because that valve lies horizontally in the set, it must be a genuine original Mullard valve. So called 'EBL31' valves on offer as New Old Stock valves from UK valve dealers are - in my experience, EBL1 side contact valves which have had an octal base skilfully fixed over the original valve base. The consequence of this is that the valve is too tall to fit in an A22 and will not allow the back to fit on the set. Also, the converted valves have a 3/8" top cap - not a 1/4" top cap as do genuine A22 valves. (You can find genuine EBL31 valves - I saw a used one today at Golborne for a sensible price, which had been tested and was good).

The beauty of the A22 is that almost all of the resistors and capacitors are on a neat tag strip fixed around the outer edge of the circular chassis, making it particularly easy to test and replace any components. In each set I restored, I had to replace several out of spec resistors (for which I used 1 Watt metal film resistors as they're similar in size to the original carbon composition ones), and I replaced all of the waxy paper caps. Unsurprisingly, the output valve bypass capacitor (25V 25 uF) was duff and needed to be replaced. As it's in an upright can above the chassis, and modern ones are so tiny in comparison, I 'stuffed' the original can with a new cap.

The makers' own Service Data (either on Paul's CDROM from the top of the screen for £1.99) is clearer than the Trader Sheet and has detailed drawings of the chassis. If you do a search on the forum for 'Ekco A22', look out for any posts by Robert Darwent, who has extensive experience on totally re-building them and has had articles on his experiences published in the BVWS Bulletin.

The A22 is in my view by far the best of the circular Eckos - it's AC only, and unlike sets such as the AD65, the chassis of which is a bit of a rat's nest, the A22 is very easy to work on and performs very well. If you intend to use the set regularly rather than put it on display, it's well worth restoring it rather than risking damage by leaving the rubber wiring in place etc, but it's not my set - it's yours, to do with as you please.

Enjoy the set, come what may!
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is offline  
Old 2nd Nov 2014, 11:41 pm   #6
Phil G4SPZ
Dekatron
 
Phil G4SPZ's Avatar
 
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,187
Default Re: Ekco A22 Advice

You lucky chap! I've no experience of restoring an A22, but if it's anything like the AD75 that I restored a while back, and other makes of set of that vintage, perished rubber insulation will almost certainly be present as David says. That said, I once met someone at a Radiophile workshop who brought along an A22 that he had pulled out of a skip. It worked perfectly. You may be equally lucky! But it's best to proceed with caution.
__________________
Phil

“The place where optimism most flourishes is the lunatic asylum” - Havelock Ellis
Phil G4SPZ is offline  
Old 3rd Nov 2014, 8:46 pm   #7
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Thanks for all the feedback! I'd really like to get this set working, if only for occasional use, so I will follow your advice and proceed with caution. The rubber wiring actually looks to be intact but I don't trust it - I've seen how it can turn into crumbs in house wiring so I wouldn't take a chance on that. I'm afraid you'll have to wait until Christmas (literally) for a progress report because I don't have time to give it the proper attention right now. In the meantime, fingers crossed the EBL31 works...

Thanks again.
PSValves is offline  
Old 3rd Nov 2014, 9:59 pm   #8
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 3,549
Default Re: Ekco A22 Advice

Good luck with the set - it's rare to see one so complete and in such good condition, the provenance of which is known.

Personally, I wouldn't give any other round Ekcos a second glance.
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is offline  
Old 6th Nov 2014, 11:57 am   #9
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Thanks, David. I will be taking good care of it.
PSValves is offline  
Old 4th Apr 2015, 10:17 am   #10
peter666
Diode
 
Join Date: Apr 2015
Location: Middelburg, Holland
Posts: 5
Default Re: Ekco A22 Advice

I have seen different speakers used in the A22.
Can anyone tell me please if it can be Original.

BTW, I am Peter from Holland and new here.
peter666 is offline  
Old 4th Apr 2015, 2:04 pm   #11
AC/HL
Moderator
 
AC/HL's Avatar
 
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 7,206
Default Re: Ekco A22 Advice

Hello Peter, and welcome.
Your question is a bit ambiguous, are you asking about a radio you have, or the one pictured above?
If you do have one, please post a picture to help with any advice.
__________________
Bill, BVWS member
AC/HL is offline  
Old 5th Apr 2015, 10:35 am   #12
peter666
Diode
 
Join Date: Apr 2015
Location: Middelburg, Holland
Posts: 5
Default Re: Ekco A22 Advice

I know that in service data sheets the loudspeaker of the A22 is as the speaker in the radio which foto has been placed here above, however very much A22 does seem to have a different loudspeaker fitted.

When I want to buy such a radio, its good to know if that other loudspeaker is also Original.
Can anyone give me the answer please?

Greetings, Peter
peter666 is offline  
Old 5th Apr 2015, 1:47 pm   #13
Robert Darwent
Heptode
 
Robert Darwent's Avatar
 
Join Date: Aug 2006
Location: Sheffield, South Yorkshire, UK
Posts: 982
Default Re: Ekco A22 Advice

There were two speaker types used by Ekco, roughly equally as common, to be found in the A22 model - please see images below.

Click image for larger version

Name:	A22-02.jpg
Views:	331
Size:	72.9 KB
ID:	106545Click image for larger version

Name:	A22-03.jpg
Views:	377
Size:	129.9 KB
ID:	106546

Of course you may come across other types as well - but it is a good bet they are not original to the set.

Regards
__________________

Robert G0UHF
www.wavesintheair.co.uk
Robert Darwent is offline  
Old 5th Apr 2015, 1:55 pm   #14
peter666
Diode
 
Join Date: Apr 2015
Location: Middelburg, Holland
Posts: 5
Default Re: Ekco A22 Advice

hello Robert,

thanks for your answer.

gr, peter.
peter666 is offline  
Old 30th Jun 2015, 2:44 pm   #15
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Okay, so after a lot of uhming and ahhing I've built myself a lamp limiter, hooked it up and fired up the set for the first time in many years. To my surprise, it appears to work very well. With no antenna plugged in, I'm still picking up several stations on MW. Sound quality is good.

The internal wiring is actually pretty sound although I'm planning to replace it anyway in due course, as well as the electrolytics which are surely nearing the end of their lives. All in all though, it's in stonking condition. Thanks again to everyone who has replied to the thread.
PSValves is offline  
Old 24th Jul 2015, 12:06 pm   #16
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Having purchased some period-coloured silicone wire from SWB-18, I've set about replacing the crumbly old stuff. It was going well until I got to the first IF transformer box. Whilst removing a particularly knackered piece of wire, I've inadvertently melted some of the wax off one of the mica caps. This was in spite of having a heat shunt clipped to the relevant leg.

Now I'm wondering, have I ruined it, or is the capacitor salvageable? If I replace the cap with a new one, will the set need re-aligning?
PSValves is offline  
Old 24th Jul 2015, 12:42 pm   #17
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,646
Default Re: Ekco A22 Advice

It'll probably be OK, but you won't find out until you try to use the set.

If you have to change it IF realignment will be required.
__________________
Graham. Forum Moderator

Keep the soldering iron hot.
Station X is offline  
Old 24th Jul 2015, 2:04 pm   #18
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Thanks Graham.
PSValves is offline  
Old 26th Jul 2015, 3:44 pm   #19
PSValves
Pentode
 
PSValves's Avatar
 
Join Date: Jul 2008
Location: Nottingham, UK.
Posts: 151
Default Re: Ekco A22 Advice

Okay, now this is confusing. One of the capacitors in the IF transformer appears to be 220pF - odd considering that both the manufacturer's and Trader schematics state all four IF caps are 100pF.

I can't understand why this would have been fitted from new or fitted by a repairer at a later date - surely it would make the whole IF section untunable?
Attached Thumbnails
Click image for larger version

Name:	IMG_7297.JPG
Views:	161
Size:	75.4 KB
ID:	111072  

Last edited by PSValves; 26th Jul 2015 at 3:45 pm. Reason: Edited to add picture
PSValves is offline  
Old 26th Jul 2015, 4:31 pm   #20
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 3,549
Default Re: Ekco A22 Advice

That does seem odd, given that it looks to be factory fitted, because if the capacitance is higher, the inductance would need to be lower to tune to the same frequency, but maybe the coil does have a lower inductance? The service data only states the DC resistance - not the inductance, and all four IFT coils are stated as 10 Ohms. (L8/9, & L15/16 on the maker's data). At least you know that it's been in your partners family for years, so doesn't have a dodgy provenance. If it seems not to have been meddled with by the 'phantom fiddler', its reasonable to assume that the set worked well enough from new.

Don't know if you have a scope and signal generator, but if so, if you connect the scope to the output of the IFT and the sig genny to the input, then sweep the generator across 465 kHz, you should see a marked dip in amplitude on the scope at resonance. That's a quick and easy way of checking the IFT, even if it's out of circuit. This method of testing has the merit of being able to check the IFT with the set not operational.

I wouldn't worry about the wax being melted on the mica cap. Often they have a very thick coating, but others have just a very thin coating and seem to fare just as well over time.

Good luck with it.
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 4:57 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.