[Elecraft] New KX3 reverse voltage smoke

[Dave]

Many items of radio equipment are supplied with  a fuse in both the +ve and
-ve leads to avoid damage from missing return connections in vehicle
installations, as well as providing a fuse if the -ve rail is accidentally
connected to a +ve power supply point, where -ve at the supply connects to
ground.

Some mobile radios had a “fuse” from their power socket -ve point to
chassis inside the radio, this was a short length of tinned copper wire to
protect the wiring in case of reversed connections. I replaced a lot of
those fused links when I worked for a mobile radio manufacturer.

73 Dave G4AON
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