00107

Hans Goulooze has now modified the experimental board; today he replaced also the left-hand side of the control-panel. As to stabilise the ca. 2 kV supplied on to the crt circuitry, we added 10 BZX 200 zener diodes in series. Therefore we added in series with the HT line a 1 MΩ resistor; of course therefore the HT power supply had to be set at an increased output voltage. For two reasons, as to limit the zener current as well as to use the voltage swing across the 1MΩ series resistor.