MK125 not working properly

Hello, I have connected everything as instructed, the LDR works, delay circuit works, LD1 works, but when I connect the external light to the terminal block (-ve in NO, +ve from battery in COM) the light remains off irrespective of LD1 being on or off. When I connect the external light through COM and NC just to check that it works, it lights up so there is no problem with the external light. Could you suggest what the problem might be and if any of the components is malfunctioning?

Bad relay or bad soldering.

Thank you. I have replaced the relay because there was no sound coming from it. The new one makes no sound either. Is there a possibility that there is something wrong with the base of the relay (bottom non-detachable part)? Is there a way of checking that the relay is ok? I will re-solder anyway.

The relay should click. Possible reasons if not:

  • power supply defective (12 Volts, capable of delivering 100 mA or more?
  • bad soldering joints around relay and transistor
  • relay defective

Most likely an assemble or power supply problem.
Sorry, this forum does not allow picture uploads
If you can provide LINKS (e.g. by using a free online picture base) to HI-RES and SHARP pics of your assembly (both solder- and component side)
then we can take a look and provide some feedback.