Okay, so here's the list of IDE control signals in the empeg:

RD (read) obviously not stuck.
WR (write)
BA0,BA1,BA2 (address/register select lines)
IDECS1 (chip select)
IDECS2 (chip select)

That's mostly it. A very short list.
And since the CS4231A is also not responding,
it's most likely the pins shared with that chip.

BA0,BA1 go to both IDE and CS4231A, but not to ethernet (I think).

And the IDECS1/IDECS2 lines go only to IDE,
but they are generated by the same PEEL18CV8
that also generates the CS (Chip Select) for
the CS4231A. Perhaps the PEEL chip has died.

So.. check the lines that are in common between those
two devices (IDE, CS4231A), and see if they toggle
or are just stuck.

Cheers