Well the intermittent display fault has returned to my HP 54615B, trouble is after the second power up, the Hsync/Cal signals don't stay borked for long enough, to see if they are failing at the same time as the display, the signals are correct before the CRT fully warms up and the picture appears.
Hsync & cal signals measured, before they quickly corrected themselves to 19.72kHz (Hsync) & 1.2kHz (probe cal).
I can't find the "any" key.
David