Mother and Child dimmers

[HIDLamp]

I got asked if I could have a look at some faulty 'mother and child' dimmable halogen lamps. They said there's 4 in total and some have one light and others are totally dead. Well upon inspection and establishing that the lamps and plug fuses were ok I opened up the modules and found all the faulty ones to have something in common, all with a failed lamp had a nuked dimmer circuit. So presumably if the lamp goes dead short when it fails rather than bowing the 3A fuse in the plug it blows the dimmer instead. Quality. So for now the faulty dimmers have been by-passed so they light when plugged in untill I come up with a plan for them.

[FrontSideBus]

I'd first check to see if there was a sneaky bastard fuse on the circuit board of the dimmer unit.

[HIDLamp]

There is a soldered in one but it's only blown on 1 of them the others it's ok. There is only 1 soldered in fuse rated 2.5A on the input.

[FrontSideBus]

The main switching transistor would be my next check tbh.

[HIDLamp]

I'll have a look when I go back

[Slyspark]

To be honest, the story of most modern dimmer modules that crap themselves as soon as a lamp fails. They're just rubbish now.

[HIDLamp]

The other week when I had a small incident of putting mains up the 350mA output of a PSU not only did the PSU go bang rather spectacularly but the mains dimmer failed too. Fused at 3A. What is the point of the fuse going to be if the circuit components blow first.