"ampdoc" wrote in message
...

"David Farber" wrote in message
news:Kj_ug.9123$Oj.2015@trnddc05...
That's about as an encouraging a response as I could have hoped for.
I'll
order the uP and expect a full recovery.

Regards.

--
David Farber
David Farber's Service Center
L.A., CA

wrote in message
ups.com...
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





I think I remember these units, it's not the micro or DSP, it's the
EEPROM.
IC9374 I believe. Pain in the butt to solder in, very fine lead spacing
even
for a SMD. There was a problem with that unit, the EEPROM types were
changed, I can't remember if they went from FLASH to MASK type or the
other
way around, but changing it usually fixed the problem. In some lucky cases
you could just resolder IC9374. If you get the newer type EEPROM there are
2
jumpers (Zero ohm surface mt resistors) that have to be moved for the new
type to work, unless this unit has been repaired before.

Hope this helps.

Jammy



Hi Jammy,

I was tipped off to the resoldering fix to the EEPROM on a previous repair
of a Pioneer receiver and that's why that was the first thing I attempted.
So the question remains that if the EEPROM is defective, would that disable
the clock to the uP? Now I'm wondering about David Kuhajda's reply saying he
replaced his DSP IC whether he was talking about the uP or the EEPROM.

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