UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

frsimen · 29th Nov 2022, 8:57 pm

You could try removing the valve from the VHF tuner and applying a signal to the grid of the first IF valve. If the rustling is still present, the problem is somewhere in the IF strip, if not, it's in the tuner.

The noise getting worse with strong signals could be a component breaking down as the signal voltages increase. If the problem remains with V6 (the valve in the tuner) removed, check the components around the ratio detector which is where the largest voltages will be found with a strong signal.

Paula

29th Nov 2022, 8:57 pm	#2
frsimen Heptode Join Date: Jan 2011 Location: Croydon, London, UK. Posts: 773	Re: Cossor 524 rustling noise on FM You could try removing the valve from the VHF tuner and applying a signal to the grid of the first IF valve. If the rustling is still present, the problem is somewhere in the IF strip, if not, it's in the tuner. The noise getting worse with strong signals could be a component breaking down as the signal voltages increase. If the problem remains with V6 (the valve in the tuner) removed, check the components around the ratio detector which is where the largest voltages will be found with a strong signal. Paula