It was decoded to replace the existing light fittings in the hall, lounge room and the second and third bedrooms.

Did a search and found a local (Aus) supplier. Price was reasonable so 5 units were purchased.

The sparky came and the downlights were quickly installed. The sparky said now was the time to test them.

Hall - yes.

Lounge one - yes.

Lounge two - yes.

Third bedroom - yes.

Second bedroom - no.

Sparky went out to his van and came back with some form of tester. Plugged it into the socket and it light up as it should.

Damn. A dud downlight.

Another search because the original supplier did not have them any more. Found another local supplier cheaper than the original units. One was ordered and it arrived in about 5 days.

Removed the dud downlight, plugged in the new one and there was light.

OK. Time to determine what was wrong with the original unit. Unscrewed the only screw - for the cable clamp - and noticed that nothing else was accessible. Damn - what if something was wrong with the circuit board? Unscrew the live and neutral leads. Wow - really nice with ferrules around the wires. Out with the multimeter to check each lead. One was good and no meter movement with the other lead. Hmm! Snip both ferrules off and prepare new ends. Screw them back in place and "Damn" nothing.

Found another plug with twin lead and prepared the ends, screwed them in and switch on. Success!

What are the chances that the lead would be faulty?