I have a Kaon satellite/terrestrial decoder that while starting up it
will reboot several times until it works. After a lot of checking and
testing it seems the front panel micro AT89S52 sometimes won't wait
long enough for all the hardware to initialize. Precise measurements
on the communications between this micro and the main video decoder
reveal that the hardware initializes always at the same speed and it
is the AT89S52 micro that sometimes waits longer and thus starts
successfully but sometimes aborts too early. I don't know what else to
check: supply 5V to the micro perfectly clean, even added capacitors
to check, clock clean (has its own 12MHz crystal). Don't know what
else to check, I can only conclude the micro is faulty. Unfortunately
I don't have the code that runs inside so I don't know if that delay
is implemented by a loop or a hardware timer.
Any ideas?