Ekco U319 RF Alignment problem - UK Vintage Radio Repair and Restoration Discussion Forum

AD360 Rob · 4th Jun 2018, 9:15 pm

Evening all,

I have had one of these sets for many years and indeed it was one of the first sets I restored but it's always been missing one of the centre knobs. Anyway to cut a long story short, I came across another at a Radiophile auction last year, it was in a very sorry looking state, filthy dirty with corrosion/ tarnishing on the brass trim strip that separates the tuning scale from the loudspeaker cloth but, it had a full compliment of knobs and was only £4. So I bought it with a view to just nicking the knob for my other one and moving on the remains. Well as I'm sure lots of you know, things never go as planned and upon removing the back and seeing decades worth of undisturbed dust and grime, I started feeling sorry for it and have embarked on it's restoration. The cabinet came up a treat after a wash and polish, all tarnish removed from the brasswork it really looks quite smart.
I replaced all the nasty (and in a lot of cases crumbly) hunts mouldseals and the few waxies, checked all the electrolytics and found them surprisingly ok so I powered up. Not a great deal happened at first but after a while, up came the AM side but rather quiet, not very lively at all. FM was dead. Shoving a signal into the AM side revealed that it was working byt needed alignment, FM was sorted with a N.O.S. UCC 85.
The issue I am having with AM is that I can't peak the set. I.F hasn't been touched by me or anyone else and I'm inclined to leave it be.
If I follow the AM rf alignment procedure, I can get the set working at the correct points and it tracks well BUT, if I touch the aerial coil for MW I get a massive improvement in signal strength. The aerial trimmer is adjusted to the end of its thread (i.e loose as can be) but there's always more to be had when I touch the coil. I've tried offsetting the local oscillator and whilst this does improve things there's still more available. Does anyone have any ideas what's wrong? It's definitely an AM problem as my other one works as it should.

Cheers
Rob

Nuvistor · 4th Jun 2018, 9:25 pm

Are there any broken connections on the ferrite rod? I think this is the model with the facility to rotate the ferrite rod.

AD360 Rob · 4th Jun 2018, 10:53 pm

Hi Nuvistor, yes you're right, this is the model with the rotatable Am antenna. I have examined the coils and connections closely and can find no signs of damage or broken wires. It behaves like it needs some extra capacitance adding. I could try changing all the fixed caps in the antenna circuit.

Nuvistor · 5th Jun 2018, 12:11 am

C9 is worth checking which if faulty will stop the RF stages tuning, it is probably ceramic and OK though.

Kentode · 5th Jun 2018, 6:34 am

Quote:

Originally Posted by AD360 Rob

It behaves like it needs some extra capacitance adding. I could try changing all the fixed caps in the antenna circuit.

Hi Rob, if I was going to do this I'd make a diagram and remove, label, measure and record each capacitor one at a time. That way they could all be returned to their original places if it doesn't solve the problem.

Nuvistor · 5th Jun 2018, 7:42 am

Did you check the coils, wiring and switch for continuity?

Chris55000 · 5th Jun 2018, 9:56 pm

Hi!

Is the set's aerial circuit "bottom–end coupled"?

This can be recognised by a fixed capacitor of 1000–5000p typically between the bottom end of both the ferrite–rod aerial coils and chassis, with an external aerial fed into the set via another safety isolating capacitor to this point.

If the bottom - end coupler goes o/c., there will be a marked loss of sensitivity and you'll also find that neither aerial coil will trim or align property!

A sudden increase of sensitivity when a hand is brought near the coils is another typical symptom of a bottom–end coupling circuit fault!

Look up "Bottom End Coupling" in the Radio Constructor section of the American Radio History site, Smithy did an article on Bottom End Coupled aerial circuits about 1961/1962!

Chris Williams

Nuvistor · 5th Jun 2018, 11:02 pm

I think that is C9 Chris.

AD360 Rob · 6th Jun 2018, 6:37 am

Morning chaps, I've checked the coils for continuity and all is well there along with the bandswitching. Next is C9 which is indeed a ceramic variety. I'll report back when I've replaced it.

AD360 Rob · 7th Jun 2018, 11:07 am

Morning chaps, well, C9 was checked (by substitution) and found to be fine. I rechecked all the aerial coils and their connections just to be sure and again, they're all fine so I am a bit stumped at the moment. To be honest, it receives the 2 stations I listen to on MW well enough sofor now at least, I'll put the back on and just use it especially as there are another couple of sets demanding attention. Thanks for all the suggestions and I'll nodoubt revisit this thread in the future.

Rob

Nuvistor · 7th Jun 2018, 11:10 am

Just one last thought, is it possible the aerial wiring was broken in the past and connected back incorrectly?

ms660 · 7th Jun 2018, 11:17 am

Does LF MW peak when sliding the MW coil along the ferrite rod?

Lawrence.

Nuvistor · 7th Jun 2018, 11:22 am

I forget to ask these questions, I shouldn’t presume they have been tried.

AD360 Rob · 7th Jun 2018, 9:18 pm

Hi all, The aerial wiring to the ferrite rod looks to be completely original with no evidence of soldering although anything is possible.
LF medium wave does peak when moving the MW coil up and down the ferrite although it's not a very big peak it is definite. One day soon I'll drag out my other one of these and see what I get on that one.

Rob

4th Jun 2018, 9:15 pm	#1
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Ekco U319 RF Alignment problem Evening all, I have had one of these sets for many years and indeed it was one of the first sets I restored but it's always been missing one of the centre knobs. Anyway to cut a long story short, I came across another at a Radiophile auction last year, it was in a very sorry looking state, filthy dirty with corrosion/ tarnishing on the brass trim strip that separates the tuning scale from the loudspeaker cloth but, it had a full compliment of knobs and was only £4. So I bought it with a view to just nicking the knob for my other one and moving on the remains. Well as I'm sure lots of you know, things never go as planned and upon removing the back and seeing decades worth of undisturbed dust and grime, I started feeling sorry for it and have embarked on it's restoration. The cabinet came up a treat after a wash and polish, all tarnish removed from the brasswork it really looks quite smart. I replaced all the nasty (and in a lot of cases crumbly) hunts mouldseals and the few waxies, checked all the electrolytics and found them surprisingly ok so I powered up. Not a great deal happened at first but after a while, up came the AM side but rather quiet, not very lively at all. FM was dead. Shoving a signal into the AM side revealed that it was working byt needed alignment, FM was sorted with a N.O.S. UCC 85. The issue I am having with AM is that I can't peak the set. I.F hasn't been touched by me or anyone else and I'm inclined to leave it be. If I follow the AM rf alignment procedure, I can get the set working at the correct points and it tracks well BUT, if I touch the aerial coil for MW I get a massive improvement in signal strength. The aerial trimmer is adjusted to the end of its thread (i.e loose as can be) but there's always more to be had when I touch the coil. I've tried offsetting the local oscillator and whilst this does improve things there's still more available. Does anyone have any ideas what's wrong? It's definitely an AM problem as my other one works as it should. Cheers Rob

4th Jun 2018, 9:25 pm	#2
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem Are there any broken connections on the ferrite rod? I think this is the model with the facility to rotate the ferrite rod. __________________ Frank

4th Jun 2018, 10:53 pm	#3
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Re: Ekco U319 RF Alignment problem Hi Nuvistor, yes you're right, this is the model with the rotatable Am antenna. I have examined the coils and connections closely and can find no signs of damage or broken wires. It behaves like it needs some extra capacitance adding. I could try changing all the fixed caps in the antenna circuit.

5th Jun 2018, 12:11 am	#4
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem C9 is worth checking which if faulty will stop the RF stages tuning, it is probably ceramic and OK though. __________________ Frank

5th Jun 2018, 7:42 am	#6
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem Did you check the coils, wiring and switch for continuity? __________________ Frank

5th Jun 2018, 9:56 pm	#7
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,864	Re: Ekco U319 RF Alignment problem Hi! Is the set's aerial circuit "bottom–end coupled"? This can be recognised by a fixed capacitor of 1000–5000p typically between the bottom end of both the ferrite–rod aerial coils and chassis, with an external aerial fed into the set via another safety isolating capacitor to this point. If the bottom - end coupler goes o/c., there will be a marked loss of sensitivity and you'll also find that neither aerial coil will trim or align property! A sudden increase of sensitivity when a hand is brought near the coils is another typical symptom of a bottom–end coupling circuit fault! Look up "Bottom End Coupling" in the Radio Constructor section of the American Radio History site, Smithy did an article on Bottom End Coupled aerial circuits about 1961/1962! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

5th Jun 2018, 11:02 pm	#8
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem I think that is C9 Chris. __________________ Frank

6th Jun 2018, 6:37 am	#9
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Re: Ekco U319 RF Alignment problem Morning chaps, I've checked the coils for continuity and all is well there along with the bandswitching. Next is C9 which is indeed a ceramic variety. I'll report back when I've replaced it.

7th Jun 2018, 11:07 am	#10
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Re: Ekco U319 RF Alignment problem Morning chaps, well, C9 was checked (by substitution) and found to be fine. I rechecked all the aerial coils and their connections just to be sure and again, they're all fine so I am a bit stumped at the moment. To be honest, it receives the 2 stations I listen to on MW well enough sofor now at least, I'll put the back on and just use it especially as there are another couple of sets demanding attention. Thanks for all the suggestions and I'll nodoubt revisit this thread in the future. Rob

7th Jun 2018, 11:10 am	#11
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem Just one last thought, is it possible the aerial wiring was broken in the past and connected back incorrectly? __________________ Frank

7th Jun 2018, 11:17 am	#12
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Ekco U319 RF Alignment problem Does LF MW peak when sliding the MW coil along the ferrite rod? Lawrence.

7th Jun 2018, 11:22 am	#13
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,431	Re: Ekco U319 RF Alignment problem I forget to ask these questions, I shouldn’t presume they have been tried. __________________ Frank

7th Jun 2018, 9:18 pm	#14
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Re: Ekco U319 RF Alignment problem Hi all, The aerial wiring to the ferrite rod looks to be completely original with no evidence of soldering although anything is possible. LF medium wave does peak when moving the MW coil up and down the ferrite although it's not a very big peak it is definite. One day soon I'll drag out my other one of these and see what I get on that one. Rob