Sony TVP-08, Training Manual

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This display can be cleared by pressing 8 and Enter in this mode.
There may be situations when the diagnostic system will not work. These
situations generally occur when there are power supply problems with
the set. When this occurs, the LED will blink continuously at .3 second
intervals. More information on troubleshooting these problems will be
covered in the power supply section. Keep in mind that other power sup-
ply problems could cause a false indication to be given by the Self-Diag-
nostic section.
Circuit Description
All of the circuits that can be indicated by the self-diagnostic have an
input to IC1009 OSD CPU, except for the AKB circuit. The indication from
AKB is sent over the I²C data lines to IC1008 Main CPU. This data is
then sent to IC1009 OSD CPU to be displayed. These indicators are
from protection circuits, which will be discussed in more detail in the indi-
vidual circuit descriptions. They all output a HIGH when they are acti-
vated. When a failure is received from one of the circuits, it is stored in
IC1007 NVM. This can be helpful when problems are intermittent. Keep
in mind that failures might not always indicate the correct circuit. For
example, if there is an intermittent HV failure, the indication could be
displayed as AKB failure.
In addition to sending a signal to the OSD processor, all of these protect
lines are connected to the power supply latch on the G board, except for
AKB and HV. This means that if there is a protect condition indicated by
any circuit except AKB or HV, the set will shut down. When the set shuts
down, the Timer LED will blink as stated previously. The set must be
unplugged before you can attempt to operate it when a shutdown occurs.
There is also an additional LVP circuit on the G board that will not be
indicated when a failure occurs. This is due to a problem in this area that
causes a number of dilemmas and usually occurs too quickly for an indi-
cation to be given. When there is a failure in this area, the Timer LED will
flash continuously every .3 seconds.