On Tue, 25 Feb 2020 10:48:15 -0500, legg wrote:

I had a Baku 601D hot air reflow soldering station smoke
on my bench over the weekend, with all switches 'off'.
It's not CSA or UL (or anything else)

It was a transformer failure. None of the front panel
switches actually disconnect the line. Only protection
was an 8A fast blow fuse. It had blown sometime before
the plug was pulled, so I guess it did its job.

The hot air gun is directly live through a triac circuit
at all times that it's plugged in.

I've rewound a new transformer, with a thermal link, higher
temperature bobbin/wire. It will have its own fuse.
Will also repurpose one of the front panel switches to
disconnect the AC line and add a ground wire on the line
cord.

. . . . of course it's still not CSA or UL.

RL

The original fault was due to a fan speed control circuit
failure, shorting a low-power secondary transformer winding.

This would have been simply repairable, with a separate
properly-sized primary fuse for the transformer.

It would not have occurred, unattended, with a proper line
power switch.

RL