UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Regentone A133 HT smoothing capacitors, V4 cathode resistor

G6Tanuki · 20th Sep 2019, 9:10 pm

The EL41 (and its designed-for-series-heater-chain sidekick the UL41) is renowned for internal leakage that can put a positive bias on the control-grid, and give the excess-current effect you've noted.

Various people (myself included) have over the years tried a range of different ways of 'zapping' the conductive film within the valve that causes this leakage, and report different levels of success.

20th Sep 2019, 9:10 pm	#19
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,995	Re: Regentone A133 HT smoothing capacitors, V4 cathode resistor The EL41 (and its designed-for-series-heater-chain sidekick the UL41) is renowned for internal leakage that can put a positive bias on the control-grid, and give the excess-current effect you've noted. Various people (myself included) have over the years tried a range of different ways of 'zapping' the conductive film within the valve that causes this leakage, and report different levels of success.