Peter, are you sure you haven’t accidentally turn them off? Of course that would be too easy a fix. It seems that 8 volt grain of rice bulb are the same as hen’s teeth. How about prewired SMD LEDs? They are smaller than the grain of rice bulb. You can get 25 for $10 at Amazon. You will need a resistor and a diode to knock 8 volts down to 3 volts. There should be enough room in the smoke box to fit them.
I am not an expert on this, hopefully, someone who knows more can give you some specifics for the resistor size and diode.