On 24 abr, 00:42, Rich Webb wrote:
Humph. So much for the easy fix. *;-)

Any chance that the manufacturer has a firmware fix for this? The
AT89S52 is in-system programmable so it might be possible to load new
firmware in the field. If there is such a thing available they may not
want to release it to an end user (too much chance of bricking the unit)
but you sound like you know what you're doing and *if* there is one
available you might be able to convince them you're okay.

Otherwise, it may be time to get creative. One possibility might be to
run the CPU at a slightly slower speed by increasing the load capacitors
at the crystal. Or, replace the 12 MHz crystal with an 11.0592 MHz
(should be available). Might work, depending on what other timing
sensitive parts that it talks to.

--
Rich Webb * * Norfolk, VA

Unfortunately Kaon appears to have removed any support for this model
from their web and months ago I sent them an email asking for a
firmware upgrade and got no reply.
When this box was given to me it had an older firmware version and it
was so buggy it rendered the box useless, this is why it was given to
me. In that time some channels started transmitting some sort of DVB
subtitles that caused it to hang. I upgraded the firmware to the
latest I could find out there and that fixed many bugs including the
hang with subtitles. I then noticed the reboot problem, but I don't
know if it existed with the previous firmware. Since it was so
intermittent and difficult to trace I decided to keep using the
decoder and see if it would get worse or fail completely but after two
years it has not changed its behavior.
Now that you mention the firmware I will look at it again. Maybe I
should try to install some intermediate version in the hope it will
upgrade the code in the Atmel. Maybe I jumped too far from a too old
version.

If it were easier to remove the crystal I would have already tried a
lower frequency one but it is sandwiched under the VFD panel. I tried
to put a lower frequency crystal in parallel to the current one but it
makes no difference, maybe the current one has lower impedance? Anyway
I think lowering the frequency will break programmed recordings which
is one of the interesting features of this decoder, since the Atmel
keeps a clock and at least the time it has to power on to start a
recording (I believe programmed recordings work this way since it is
the only alive processor while in st-by). By the way, when it awakes
to perform a programmed recording it has the same reboot behavior.