10-07-2022, 05:23 PM
(This post was last modified: 10-07-2022, 05:24 PM by Murphyv310.)
Hi.
Over the years I've discovered that when offering sound advice it's not taken up, it could be a post is missed or its dismissed as wrong. The issue with this radio is common with PCB’s of the age. They are paper based effectively and damp storage or carbonising can cause leakage. Ideally lifting components will be a cure but it's not always possible. Some plastic bases are known to leak as well, I've had to replace many in my work and hobby. There are workarounds, for example decrease the grid leak resistor value or/and increase the value of the cathode resistor either will remove the positive potential on the control grid WRT cathode and reduce cathode current and obviously anode current with the benefit of protecting the output valve and transformer.
Over the years I've discovered that when offering sound advice it's not taken up, it could be a post is missed or its dismissed as wrong. The issue with this radio is common with PCB’s of the age. They are paper based effectively and damp storage or carbonising can cause leakage. Ideally lifting components will be a cure but it's not always possible. Some plastic bases are known to leak as well, I've had to replace many in my work and hobby. There are workarounds, for example decrease the grid leak resistor value or/and increase the value of the cathode resistor either will remove the positive potential on the control grid WRT cathode and reduce cathode current and obviously anode current with the benefit of protecting the output valve and transformer.
