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sobell1980 · 11th Oct 2014, 8:30 am

I fitted an AA battery to LT supply. The set immediately burst into life, picking up absolute radio very strongly. I changed the selenium rectifier along time ago for a couple of diodes giving me my 1.3 volts to the heaters. Obviously this is not enough for a low emission valve. I need to change the value of L 17 to bring the voltage up. Because L17 is a choke can i substitute this for a modern day resistor? Also would anyone know what the total current draw of the heaters is so i can do yhe maths to work out a new value resistor? I have about 1.90 v after my diodes that replaced mr2. After L17 i have 1.3v. The value of L17 is 2.7 ohms. Which points would be best to connect my meter in series to measure my total current draw? I can then work out my new tesistor value. Many thanks.
Dave.

11th Oct 2014, 8:30 am	#73
sobell1980 Octode Join Date: May 2011 Location: Bromyard, Herefordshire, UK. Posts: 1,241	Re: Roberts RMB Problems I fitted an AA battery to LT supply. The set immediately burst into life, picking up absolute radio very strongly. I changed the selenium rectifier along time ago for a couple of diodes giving me my 1.3 volts to the heaters. Obviously this is not enough for a low emission valve. I need to change the value of L 17 to bring the voltage up. Because L17 is a choke can i substitute this for a modern day resistor? Also would anyone know what the total current draw of the heaters is so i can do yhe maths to work out a new value resistor? I have about 1.90 v after my diodes that replaced mr2. After L17 i have 1.3v. The value of L17 is 2.7 ohms. Which points would be best to connect my meter in series to measure my total current draw? I can then work out my new tesistor value. Many thanks. Dave.