[FERNSEH]

The GEC BT5144 on test. The RM4 metal rectifier was replaced with a BY127 silicon diode. A 30 ohm series resistor has been added to compensate for the lower forward voltage of the silicon diode compared with old type selenium rectifier. The 30 ohm resistor is a convenient test point to measure the HT current. When the receiver was supplied from the bridge rectifier the voltage drop measured 6.5volts. After removing the bridge rectifier the voltage drop across the 30ohm resistor is 7.9 volts.
I might add that when the bridge rectifier was in the mains input the HT rose by 30volts and to return the HT supply to the correct value the variac had to be turned down to 205 volts.
The test receiver is now supplied direct from the mains which measures here as 242volts. The HT voltage has risen slightly and is nearer 230 volts, also now that the power supply only receives the positive half cycles at the 20mS rate the reservoir capacitor current has risen to 2amps during those positive half cycles. The discharge current during non conduction period of the rectifier is up slightly to 275mA.
Although the Pilot PT650 employs a 110 degree wide angle deflection CRT the total HT current demand will be thanks to the improved efficiency of the line timebase circuits very similar to the old GEC set I've used for the experiments.

DFWB.