I'm quoting myself because I simulated the circuit and I couldn't get it to oscillate until the photocell resistance was 50k or larger (C = 0.1u). The PC SFE sells will quite likely not work.Mee_n_Mac:
What photocell did you use ? They do vary and the one SFE sells may be different in it’s range of resistance from the one used waaaay back when. You might try a resistor in place of the photocell, values ranging from 1k, 10k, 50k, 100k.