Bose soundtouch 30 common module

[spd]

I am trying to repair a bose soundtouch 30 series iii which has no display or sound.I found service manuals for series 2 and 3 on the internet but no circuit diagram. It seems the series 3 input output board 716469-0050 is very much different from series 2. I wonder if these are interchangeable?
I think the other modules (power board and input output board are OK).
Has anybody ever tried to repair these and know what is the most common fault.
Thanks.
spd

[spd]

Further my earlier message, I am able to see some voltages on the ic's though I haven't checked in detail, but there is a diode array DT1042-04TS-7   which is perhaps connected to a coil or transformer, which shows zero voltage on all its 6 terminals.
The continuity also shows zero ohms in both directions, I have not taken it out of the circuit to check.
Perhaps somebody here can guide me if this is how it should be.
Thanks.
spd