"Franc Zabkar" wrote in message
...
On Wed, 05 Mar 2008 14:15:01 GMT, "Arfa Daily"
put finger to keyboard and composed:

Anybody come across this one as a 'stock' fault ? Got one on the bench now
that comes out of standby with the immediate message "CHECK DSP ROM".
Bootup
continues normally with protect relays dropping in ok, and unit settles
with
"DVD DIG.4-AT" in the display, and that's it. Unable then to select any
other mode, or invoke any function either front panel or remote, except
the
front panel volume control, where the display correctly shows volume
control
action, before dropping back to DVD message again. Have tried a factory
reset, which seemed to take place ok with the display saying "DEFAULT" and
the amp carrying out a basic full restart, but symptoms remain.

Anyone know this problem on this model, before I have to start diving in
and
ordering service manuals etc ?

Arfa

I have no experience with this model, but its specs state that ...

"Latest generation of DSP from Cirrus Logic decodes DTS ES, 96/24
decoding, Dolby Digital EX, Dolby Pro-Logic II and Circle Surround
6.1"

I'd look for a CL chip and download its datasheet. If there is a
separate ROM/Flash/EPROM chip in the vicinity of the DSP, then I
suspect it is failing a checksum test on power-up. If the ROM is
on-chip, then I expect you'll need to order the DSP from
Marantz/Philips.

- Franc Zabkar

Hi Franc

One of the others has fixed me up with some service info now, and the
message in question is mentioned in the "errors" section as representing an
issue with the DSP's code, as opposed to a comms problem between the DSP and
the system control micro, which producs the slightly simpler message of
"CHECK DSP". So yes, I agree with you. I think it's going to be a boot
sequence checksum error. I'll start by having a look at the schematics to
see if the DSP is internally coded, or has an external ROM glued to it. I
suspect from the message, that it is going to be the latter. Hopefully, it
will then prove to be something nice and simple like a crapped out lead-free
joint or two on either the ROM or DSP.

Arfa
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