EKCO A320

[Radio Fixer]

I have an Ekco A320 to service (certainly not restore as I mean it).

It belongs to my Yoga Guru's and has been in regular use for decades. The cabinet is in poor shape but it was only cheaply finished in the first place. Just some toner lacquer blown over the raw ply. But its solid and has no worm. Amazingly the grill cloth with a string overlay is quite good.

Valve technology was certainly meant to last, and in many cases it has. This old thing still works on all wavebands and actually sounds pretty good on FM whilst apparently never having had a soldering iron on since it was made. Even the valves may be original, anyway they are all Mullard with the same amount of dirt.

So what to do with it ? All I have been asked to do is stop the crackle from the waveband switch and volume control although on first play that seems OK to me.

So far I have cleaned the chassis with a brush and a vac and the inside of the cabinet (10 mm of dust in the bottom).

I'm tempted to do something with the cabinet, rub down and a bit of dark toner perhaps ... but once you start these things ...

So maybe do as asked and possibly change the grid cap of the O/P valve. The can electrolytic is obviously still doing its job as there is no hum and it has no bulges, so leave it be?

Easy to get enthusiastic and its really just an old dog but one that still barks.

I may actually have been working at Ekco when it was made but who remembers square boxes.



Gary

[AlanBeckett]

I may actually have been working at Ekco when it was made but who remembers square boxes.

Indeed so. People sometimes ask me the same thing about my time at a Manufacturer's. Five thousand a week went down the line and I should remember Models?

I do like a dusty old Chassis. It shows it hasn't been mucked about with. The Aerial 'Rotator' is splendid - I like it.

I suppose the answer to the re-furb level is 'Ask the owner'.

Alan

[Refugee]

The low humidity from the regular use may have kept the worm out of the wood and also the moisture out of the capacitors.
I would add the capacitor across the output valve to the grid one if they are not reliable types from new.
I bet they are mustard caps and will not need to be replaced at all.

[Radio Fixer]

Well, alas not mustards Refugee.

   

It all appears untouched. The crackle that the owner thought was the volume control was HT on a switch contact arcing to the earthed stud. Partly due to dirt but probably mainly silver migration as the contacts and rotors have that blackened silver look. So far I have given it a scrub with a stiff brush and DeOxit and that has stopped it. I will have a closer look later and maybe scrape the wafer with a scalpel or a bent warding file.

Glad it wasn't the volume / tone control as dual gang pots are tricky as often the shafts are special to the knobs !

HT measures high, the high mains input again. The EL84 grid had 4 V + on it. When the coupler cap was snipped the cathode volts and anode current dropped by a third. Wonder how the valve is: will test it later.

See someHunts brown caps ... more inspection needed.

Gary

[AlanBeckett]

Now you've bitten the Bullet there's no going back

Alan

[Radio Fixer]

Not much of a bullet to bite Alan (fingers crossed !)

Scrapped the Paxolin switch wafer and cleaned away the dust. Changed the coupling cap to the O/P valve and that to the AF pre-amp (2 M Ohm @ 25V) and it works well (very sensitive) on all wavebands. Now on soak test.

Measured the volts on the valves and they line up with the Trader Sheet. Not tested the EL84 as the cathode current is OK so emission still up.

Must say I'm impressed by the old thing: all those years and that's all it needed. Amazing that the Vol and Tone pots have no scratchy noise. Even the dial lamps are still working ! They dont make them like that anymore !

Gary

[AlanBeckett]

Splendid result.

Alan

[singlepentode69]

Proper job well built sets
Regards
Robin