John... try a hairdrier on the coils. That might free them of any damp. In mine the osc amplitude increased as the coils warmed up and remained higher after cooling.
Argus 25
See what you think re the results I obtained.
I uploaded the details of the coils and the results of my repair here
http://www.radiomuseum.co.uk/Moreton...tml#anchor4703
The oscillator circuit in the Moreton Cheyney receiver uses the triode section of a 6K8 with a tuning coil and a feedback coil. One end of each winding connect together and then via a padder to ground. The tuned circuit connects to the 6K8 grid via 100pF with the feedback winding connecting to the 6K8 triode anode via 2200pF. The trimmer for LW and MW tuning coils is 3-65pF and the oscillator coils have no dust cores so tracking was a bit hit and miss, relying on the accurate inductance of the coils. I measured one and it was 0.7% higher than the spec in uH (but my LCR meter isn't too accurate).
I'm using a NOS 6K8 in a metal envelope. The two highest SW ranges do use small dust cores so tracking places the broadcast bands correctly on the dial.
I did note that the new 6K8 performed much better than used examples so emission is a very important factor ie. even with the open circuit feedback coil.
Allan