Ekco U319. Help for a newbie, please!

[tigger449]

I inherited a Ekco U319 from an elderly uncle a while ago and have decided to try restoring it. Unfortunately, my engineering friend who used to help me with these things died a couple of years ago so I'm flying solo now!

I've powered up the Ekco and the dial lamps work but that's it. I've had a look under the chassis and spotted the black wire arrowed in the picture floating in the breeze. There's a terminal on the tone pot with no lead attached so I'm guessing it's come from there.

Am I on the right path?

[Station X]

Before we start discussing loose wires, do the valves light up?

I'm assuming they do, as otherwise the dial lamps wouldn't light up. Worth checking though.

EDIT. Where does the disconnected wire go to? If it goes to C48 (manufacturer's sheet), then the lead being disconnected could stop the radio from working depending on where the commoning point is.

[Al (astral highway)]

Originally Posted by tigger449

I inherited a Ekco U319 from an elderly uncle a while ago and have decided to try restoring it.

Nice one. There's at least one outstandingly documented repair of this set on the forum (that I remember), so can I invite you to put the make into the search engine and start there?

Also, if you are new to this business, there are a few basic things that are well defined precautions and likely fixes, before looking for anything elaborate.

If you can read and interpret a circuit diagram ( you don't say much on your profile, not a criticism, just that it leaves us guessing) it's worth downloading that for starters. I wouldn't suggest connecting a loose wire to a 'guess' location under any circumstances where it could cause devastating harm to a component.

If you applied a low impedance high voltage power source to that pot, it would go up in smoke, adding unecessary complexity to your repair/restoration.

Graham's question is a good one, although don't wait around once you've checked. It would be best to power down straight away, do some of the fixes I'm referring to (and I'm not being cryptic, just that we don't know your skill, experience, or problem-solving level yet - 'Newbie' isn't a defined thing!) and take a very measured step at a time.

There are plenty of people on the forum who will offer a safe handrail for the repair, so long as you can match that with a bit of patience, and a willingness to work carefully and methodically.

[Station X]

I see that this set has a pick up socket. Switch to gram, turn up the volume and touch each connection of the pick up socket in turn with a metallic object such as a screwdriver. If the audio stages are in order a loud hum or buzz will be heard.

[ms660]

The pics in Post#5 in the link below might help, especially if you have the schematic:

https://www.vintage-radio.net/forum/...d.php?t=125238

Lawrence.

[kalee20]

Plenty of help available! Others are already giving good advice.

The U319 is a decent set, when going properly it will give a good account of itself. Having FM is a big plus, though you'll need a reasonable VHF/FM aerial.

[tigger449]

Thanks for your help guys. I've got a copy of the wiring diagram. The loose wire is shielded and the shielding goes to C44 (from my diagram) whilst the core is grounded to the chassis. With the power on, the valves all light up and there's a slight hum from the loudspeaker.
I'm not a complete novice, but I've always had my mentor looking over my shoulder in the past - feeling a bit like a newly qualified driver glancing at the empty passenger seat on my first solo drive!

[Boater Sam]

So you are using the Manufacturers diagram.

The screened cables should have the outer braid connected to the chassis at one end ( not the core ).
The core should be connected to the wiper of the volume control, centre tag to C44 and from the other end of C44 to R20 and the grid of the triode in the UABC80 valve.
C44 is one of the capacitors that need checking carefully for leakage, C48 is the most important one "that capacitor".

[Radio Tech]

Hi

Seems a bit strange the inner conductor going to ground, are you sure this is correct, I would have thought the screen of that cable to ground. The hum is most likely due to poor smoothing electrolytic caps, they are the ones that are connected to the cathode of the rectifier valve, and if you are ok in reading the circuit diagram, look for those wax looking caps that link one stage to the next, you do not want a huge positive voltage on the grids of the valves.

And welcome to our forum

Best wishes

Ken

[tigger449]

My mistake - it is the braided shield that's connected to the chassis. My view was obscured by a large lump of dusty muck, but my multimeter confirmed the situation! The core from the centre tag of the volume pot goes to C44.

[Station X]

If you touch the disconnected end of the wire (core) with an insulated screwdriver, you should get a loud hum or buzz from the speaker.

[paulsherwin]

Just a reminder that this is a live chassis set directly connected to the mains. Check that the chassis is connected to the neutral pin of the plug, and that the socket is wired correctly (it's not unknown for sockets to have live and neutral connections reversed). It's a good idea to get into the habit of checking the chassis with a mains testing screwdriver whenever you power it up with metalwork exposed.

An old serviceman's trick is to keep one hand in your pocket when working on powered equipment. This means that any shock won't pass through your chest.

[Boater Sam]

Originally Posted by tigger449

is and spotted the black wire arrowed in the picture floating in the breeze. There's a terminal on the tone pot with no lead attached so I'm guessing it's come from there.

Am I on the right path?

Which tag has no wire? Are you sure it's the tone control? One end of the control goes to chassis, t'other end to C48 and g1 of the output valve, the centre, wiper, goes to C46.
The diagram shows no screened cable there! The only screened cable is either side of C44 and C42, near the VOLUME control. And a bit to the pickup socket.
If the cable is off the tone control, the radio would still be working.
Follow the diagram and it will be obvious where it goes.

[peter_sol]

The volume and tone controls on this set are concentric so it is easy to confuse them.

[Station X]

Looking at the picture in post #1, I can clearly see the feed through capacitor C42. A red sleeved wire from this appears to go to the end of the track of the volume control R18.

This is correct.

As for the wire "floating in the breeze", that's the black sleeved wire. If the terminated end of this goes to C44 (another feed through cap) then the unterminated end needs to be connected to the centre or wiper tag of the volume control.

However in post #10 the OP says that there's already a wire from C44 to the centre tag of the volume control.

So where does the black sleeved wire really go to?

[tigger449]

Glad to report success. Soldered the stray wire onto the correct terminal and all working. Now to think about replacing some of those dodgy caps!