15-02-2017, 08:38 AM
The solution came quickly, and unexpectedly (as it has often done with me). On trying it this morning, I found it 100% stable. I turned the HT up to 200 Volts, and the volume increased accordingly, and the stability was maitained. It is apparently funtioning perfectly! Reason - the low battery LT supply. I tried a reduced LT voltage and the instability came back. The instability was due to the LT battery running down. I had checked the battery before I started the repair, and it registered at 6.3 Volts, but two days ago, when I checked it on load to the set, it was 4 Volts, although it went back to 6 Volts off load! This would not have hapenned if I had used 6.3 Volts ac from a transformer, but I like to have an independent battery supply on projects like this. If the repair had gone quickly and smoothly, I would have gained no pleasure from it. But as it has given me a lot of brain exercise, I am now feeling pretty good about it, espcially as I have cured a large number of genuine faults along the way. Just a matter or re-wiring, and tidying it up now! 
Bob
Bob
