Two threads going with same topic.
R10 is a 680 ohm, 1%. 1% not needed but tighter tolerance won't hurt anything. Appears to be 1/4W resistor but will only be dissipating about (4*4)/680 = 0.023 Watts. To me - the color code says the part is actually 690 ohms which is a common value for 1% values. Blue, white, black, black, brown. But.. I suppose the white could be gray. Either way - 680, 690, AC, DC, that one just doesn't matter.
C2 is a non-polarized audio capacitor. Considering where it is used - not a great choice but will work.
Need to fix solder joints at E3 and E4. This very well could be the source of the 9.9V versus 8V.
What part number is installed at CR7? Check part numbers on it as it may have been substituted.
Good solder joints at both anode and cathode of CR7?
If the diode is the right part - you should be measuring 7.79V to 8.61V.
HV is bad - still need voltage measured at E2. Voltage at E2 is what sets the output voltage and gives us a starting point on where to start looking.
Fuse F7 - is that your GI fuse? If so, that doesn't go to the power supply. You may have a shorted lamp or lamp socket somewhere. Did you bump a wire to a lamp socket within the light box?