Pretty sure the 4V test point is irrelevant because it’s used for the octave switch, which you don’t have, and the fine tune pot, which shouldn’t make a big difference.
CHECK POWER ON THE 3340. Make sure you have +12 volts on pin 16 of the 3340, and make sure pin 12 connects to ground.
CHECK SUMMED CV. Make sure you have +12 volts between the first terminal of RV6 and ground, make sure the third terminal connects to ground, and adjust RV6 to get +6 volts or so from the RV6 wiper (center terminal) to ground.
If you don’t connect anything to the CV inputs you should have the following voltages at the resistors that connect to pin 15 on the 3340 (measured from the other end of the resistor to ground).
R19 0V because you have no octave switch
R24 <1V
R22 0V because you have no 1V/oct input
R25 0V because the link is unused
R20 0V because you have no CV input
R26 probably something small, turn down the RV8 trimmer if needed
R23 ~6V, same as the RV6 wiper.
These should add up to maybe 6 to 9 volts. Much higher or much lower and it may not be an audible frequency.
If you still get nothing on the outputs, my suggestion is to make an audio probe like this
and use it to listen for signals at pins 4, 8, and 10 of the 3340. Vary RV6 while you listen. If you hear anything, trace the signal from there to the output and see where it disappears.
If you have ~6V on the resistors connecting to pin 15 and no signal on the output pins, the 3340 is probably bad. As long as it’s got power and a decent summed CV, it should be making oscillations.