Confirm that the optocoupler is a NSL-32 and that the dot is in the correct position. I cannot tell from the photo.
Report all pin voltages using the standard numbering format as stated in the guides. Pin 4 should be ground (0V) and pin 7 about 9V.
The LED should be blinking at a rate controlled by the SPEED pot.
The KILL switch SW2 should pass a fixed voltage set by the BLEVEL trimmer. This should be close to 9V at the NSL-32. When SW2 is in the operating position, the voltage at NSL-32 should be varying.
WIthout a photo of the back, we cannot see if you have a bad solder joint. You can remove power and the ICs and resolder all joints including switches and pots.