[David G4EBT]

Hi all,

I've just finished renovating an Ekco A22 which was in a very sorry state.

Most of what I've had to do has been to replace perished wiring, and I've routinely replaced all the paper caps with new polypropylene ones.

I've replaced a few of the resistors which had gone high, but left in place the ones which measured OK. I haven't replaced any of the mica caps in the RF or IF stages, (they check out OK anyway) and the cores of the IFTs and RF coils are sealed with wax, and seem not to have been disturbed at any time (nor the trimmers).

Using about 20 ft of wire strung round the workshop for an aerial, the set pulls in several stations on medium and short waves, but on some stations there's a background heterodyne.

Also, at various points on the dial, there's a strong hum as though there should be a station heard, but no signals are there. Otherwise, when not tuned to a station, there's very little background hum, even with the volume turned up high.

When local stations (and distant ones on short waves) are tuned in, the set is very sweet, with no distortion.

On long waves, there only the occasional loud hum at various points on the dial, but then I don't think there's much on long waves anyway (except R4).

Any thoughts on the hum at various points, and what I might do to improve matters? I'm reluctant to start fiddling with the alignment if the symptoms I've describe point to other problems, (EG: AGC?), albeit as a first step, I should of course check the alignment.

I've given the wavechange switch a shot of servisol.

(By the way, the valves are all new/old stock, just supplied. All the voltages seem OK).

Very easy set to work on - most of the components are on a tagstrip around the outside of the rim of the circular chassis. Some nice design features too, such as the dial light travelling around the circular dial in keeping with the tuning.

Many thanks in advance for any thoughts.

David.
G4EBT