PA0O ham radio

To finish the long story about repairing The 465 is working fine now I found a solution to prevent damage by possible CRT HV flash over I just inserted a protective 860k resistor ( could be 1M ) in series with the -2450V  cicuit Cut the trace direct after the HV diode   see  below the point "test onderbroken" 860k  gave a drop of only 100V    no problem for the HV regulator the resistor can be low Wattage only 0.0116 W 100V 860k The cathode current is 116uA neglecting the low parallel load of multiple M OHm Since then only 1 time there was a breakdown of all voltages "light outage" but just switching off and on and all was working again  no collateral damage... I use the Tektronix 465 again and live with the occasional break downs until i find a KRT replacement. But  after some warm up time with break downs and return it works stable for hours. BTW a 100MHz b.t.w. Hantek DSO5102P USB Digital Storage Oscilloscope 2Channels 100MH...