UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Ferguson 621U

PJL · 4th Oct 2018, 9:02 pm

I would suggest a few voltage measurements around the output valve, particularly the grid, cathode and anode. PCB radio's are a PITA as the output valve and rectifier heat causes the PCB to be conductive or can cause dry joints. This is not helped by the set designers pushing the output valve to it's limits.

When I have restored them, I have made design changes to reduce the anode current (increased the cathode resistor and the HT dropper resistor).

4th Oct 2018, 9:02 pm	#14
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Ferguson 621U - help needed I would suggest a few voltage measurements around the output valve, particularly the grid, cathode and anode. PCB radio's are a PITA as the output valve and rectifier heat causes the PCB to be conductive or can cause dry joints. This is not helped by the set designers pushing the output valve to it's limits. When I have restored them, I have made design changes to reduce the anode current (increased the cathode resistor and the HT dropper resistor).