Something on the DSP board is locking up the I2C data bus lines.
Pretty common problem during storm season on similar Pioneer models a
several years ago.
Had my own DSP ic fail in this way. $35 flat pack ic fixed it.

David

David Farber wrote:
This Pioneer VSX-D908S analog/digital receiver will not pass any audio as
long as the dsp board is plugged into the unit.

First I'll explain what works with this set. With the dsp board removed,
all analog input functions work as long as you select the direct mode. The
direct mode bypasses the digital board completely. For example, if you've
selected CD direct (analog) for the source, there is an electronic mode
switch, located on the main control board, which selects between dsp,
direct, or 5.1. This switch will select the direct mode correctly and pass
the audio signal. What doesn't work is if you plug in the dsp board, the
audio does not pass through the same analog/digital mode selector on the
main control board even in direct (analog) mode. The dsp board is quite
complex but there is a uP there that communicates with the control board's
uP. Now here's where I have, hopefully, an easy question. Two of the pins on
the uP of the dsp board are labeled Xin and Xout and they have no signal. On
the uP of the control board, there is good signal at the uP on the Xin and
Xout terminals. Can I generalize that any uP that has two terminals labeled
Xin and Xout should have a continuous running clock signal on these two
terminals? Also, would the uP itself be the most likely failure to cause
this symptom? By the way, I spent a fair amount of time removing all the
boards and soldering numerous bad connections.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA