This is an Insignia Model: IS-HTIB102732 progressive scan home theatre DVD
receiver. It was accidentally plugged it into a 220 volt source and
"clouds" of white smoke apparently started coming out of the left hand side
where the power supply is, even though the person who did it says it wasn't
actually turned on. (surely if it was unplugged, plugging it in would put
it into stand-by mode, - it wouldnt try to turn itself ON?)

The wall fuse blew about five seconds after it started smoking.

The unit does however now turn on! And it seems to work. And I cant see
any damage to the power supply area on the left of the unit! Curiously
there is what looks like a fuse on the power supply board which doesn't even
look blown?

The problems for which it has come to me are that it seems to have lost
dynamic range (though I have no way of knowing what dynamic range it had
before it started smoking), the left front channel power seems very low and
the DVD displays for a few minutes then the picture gets very choppy.

Does anyone know if any of this can be traced to whatever is powered when
the unit is in standby mode? Logic seems to dictate that the only thing
needed to be powered wjem in standby mode is the remote unit and that seems
to be working.

I have difficulty in believing that the left hand power transistors or the
servos to the DVD laser were powered when the smoke incident took place.

It does tout itself as a 1000 watt unit which seems to me more than a bit
like a very 1960s looking figure. The speakers are incredibly tinny looking
and the sub is made predominantly of particle board. The unit has no weight
to speak of to support any sort of power transformers supplying 1000 watt
transistors and heat sinking to them looks minimal. I suspect the impedance
is under an Ohm (and I have it connected to ordinary 8 ohm speakers at the
front)

(Yes, it IS made in China)