I changed R803 the 56k anode resistor for V814 to 68k to reduce V800's screen grid voltage, & adjusted the EHT to minimum. The CRT display is a lot less bright but I still have no intensity adj and the display is still half width of the CRT. The OP of V800 is way lower than spec. I can only suppose the forward bias V of the silicon diodes is less than a 5642 valve diode: the datasheet gives no voltage spec.
Next I'll check all the resistors in the potential dividers that feed the focus & intensity pots and power supplies again. BTW I have limited focus adj.
Andy.
Diabolical Artificer