I know that this reply is kinda late (OP was Feb 28), but more recently
I came across an excerpt from the schematic:
http://www.radioscanner.ru/uploader/2006/icfsw30.djvu
As one can see, the MW frontend is quite simple, similar to e.g. the
ICF-7601. Possible causes of no AM but everything else working thus
could be:
* One wire of the antenna coil L16 (or the center tap) has become
disconnected. Should be relatively easy to check.
* No LO output. Use another rx to check for the LO het 450 kHz above
nominally received frequency. If this is not present, it's either a
problem with the LO or the PLL (for which I don't have a schematic).
* Dead MW mixer. This is not unlikely given the sudden appearance of the
problem (which frequently indicates a semiconductor defect) and would
be toughest to fix, requiring replacement of the CX20111 (a 24-pin SOP
part). It looks like this chip was produced at least until 2000 and is
still obtainable.

Stephan
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