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

julie_m · 13th Oct 2019, 5:52 pm

Another way to do it: Meter on AC volts, across heater pins of valve. Set on and warmed up.
Record voltage V.
Switch off power to set.
Switch meter to ohms.
Record resistance R. (Quickly! -- it will change as the valve cools.)
Calculate current using I = V / R.
Disconnect meter (or at least, switch back to volts) before reapplying power to the set.

13th Oct 2019, 5:52 pm	#105
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Philips BX281U20 valve radio Another way to do it: Meter on AC volts, across heater pins of valve. Set on and warmed up. Record voltage V. Switch off power to set. Switch meter to ohms. Record resistance R. (Quickly! -- it will change as the valve cools.) Calculate current using I = V / R. Disconnect meter (or at least, switch back to volts) before reapplying power to the set. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.