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rogerdup · 24th Jul 2018, 6:44 am

That's interesting. I know that static crt's are very sensitive to field radiations, but not imagined that the eht supply could have been in cause because of the shield.
Perhaps an induction in the two wires which give DC power to the 12SN7 oscillator. May be trying a decoupling on these wires after the 150 ohms serie resistors would be useful. I would say 1n to 5n / 630v capacitors to the ground. Could be also an interference coming through the 12SN7 heater?.. I will try that.

24th Jul 2018, 6:44 am	#69
rogerdup Retired Dormant Member Join Date: Jan 2018 Location: Chamalières, France. Posts: 167	Re: Firestone 13G3 Television That's interesting. I know that static crt's are very sensitive to field radiations, but not imagined that the eht supply could have been in cause because of the shield. Perhaps an induction in the two wires which give DC power to the 12SN7 oscillator. May be trying a decoupling on these wires after the 150 ohms serie resistors would be useful. I would say 1n to 5n / 630v capacitors to the ground. Could be also an interference coming through the 12SN7 heater?.. I will try that. Last edited by rogerdup; 24th Jul 2018 at 6:56 am.