Perhaps a reset problem. Touching header J301 p10 with a probe, kills
the noise and normal function seems to resume.
The LD1 red LED flashing seems to be normal function.
AT POST the sequence is 2 second off, 1.5 sec flashing, 1.5 sec off,
then continuous flashing.
Finger injection of EMI the noise goes immediately and flashing LED
goes off for 2 sec, 1.5 sec on, then continous flashing.
p10 connects round the houses of the DSP board via a jumpered J101 for
some other option, to what I assume is some sort of control processor
with 32M of memory, has Helicon label v1.2.01 on it.
Under is Spansion S29AL032 then looks like 070TF103.
Datasheet not found on spansion.com but their numbering seems to be
letter not 0 (or O) after the 032, but suffix TF103 part is similar to
other devices of theirs.
Will trace the other way to the display board which is still in the casing