Philips Diagnost error 3960

is this error appearing after an exposure? if so could be a tube arc.

3960 Emergency off from unknown source
Hardware ready 2 disappears
Error occurs after EXON (> 75% kV) signal is seen
when PREP request signal is taken back
• If followed by error 3275: check for flashing, arcing tube,
measure mA at EZ126 X32 TCUAVLI (1V-0.2666A / 3.75V-1A),
check EH136 / EH141 R1for bouncing slider.
• If error is mA dependent, check proper contacts on frequency
relays.
• Measure DC power supply signal during exposure at EH102
X1:B32 - start with 10 kW exposures and increase in 10 kW
steps, the voltage should be (ca.) 8.5 to 9 V. (this value should
not drop more than 1 V).
• If in combination with 1576 / 3960 / 3974: Check impedance of
resistors EQ100 R5 to R8 or EQ200 R3, R4, R6, R7 (1 MΩ
each) (PCB version dependent) and check for proper connection
to EH102 X41 (pink/orange line).
• If adaptation gives no constantly rising currents (jumping values
up and down) or if in combination with 3275 during application:
clean the cathode high voltage plug pins on the tube side (there
should not be any silicone on them). Do the same with tube
sockets, widen the pins carefully, put the 3 hole silicon disc back
on the plug, and only use silicone paste on each side of the disc,
in the size of a pea.
• If in connection with TDC and/or 3986 / 3988:
– Try to optimize the mA start value.
– Replace the measuring chamber.
– If start mA is 10 mA, try lower kV or pre-filtering.
• Check for rotating anode and proper speed. RCTBSP rotor
control tube set point EH131 X2D:26 and VOCH voltage check
EH131 X24, must have the same value (see tube data list) at the
end of preparation (for SRC, see SRC rotor control).