My trusty old Fireface 400 has started shwoing signs of fatigue since a few days:
the leds on the front panel are half lit and cycle randomly, and I can also hear a distinct high pitched coil whine.

The unit is powered via an external PSU (checked and fine, outputting 12V).
When I power on the PC for a few minutes (with FW connected), power cycle and start again,
the leds go back on and the FF connects to the PC normally (host led goes from red to green).

That looks suspiciously lilke a capacitor failure somewhere in the unit, so I opened it and looked for blown electrolytics,
but they all look quite normal, except for some kind of light brownish dust at the base of some of those capacitors.

Do you think I should attempt to replace the internal PSU / filtering caps (the large ones on the logic pcb close to the coils)
and that might fix the problem ?

Thanks for any hints,
Lorcan