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Sony CXA2092Q mpeg decoder (in Nokia DVB 9850T)

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Jan 1, 1970
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I'm trying to fix this "ITV digital" UK DVB-T receiver.

Symptom is no audio and dreadful video quality (both scart and RF).
Video amplitude is very low and noisy, my TV barely manages to sync
and display it, though it is visible enough to allow one to see
that the digital decoding is ok. One can just about see enough
to navigate the menus, which all seem to work.

I suspected a power problem on the analog buffering, however
all caps ESR ok and rails (as far as I can guess what they should
be) seem ok. The outputs are buffered with discrete transistors
(emitter followers) which seem to be working ok but receiving
a dreadful input.

This box uses a Sony CXA2092Q chip to generate the video, so
it would be a natural place to continue debug. (I guess it
sources the audio too.) Maybe it's missing a power supply?
However I've been unable to find any datasheet for this chip
with Google (only the usual Chinese sites selling parts...)

It's a multi-layer PCB (with most signals on internal planes)
and hence a nightmare to trace.

Does anyone out there have info either on the Sony CXA2092Q chip
(just a pinout would be a huge help) or maybe schematics for
the Nokia DVB 9850T box? Alternatively, pointers to schematics
for any other device using the CXA2092Q which might reveal a
typical usage, voltages etc? I'd guess this chip is used in
a variety of MPEG-2 video devices (satellite, DVB, cable etc).

Thanks for your help.

Mike.
 
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