SOS Detection Circuits
SOS Detect (D Board)
The GPH8DU chassis
have several protection
circuits that are designed
to protect the receiver from
major damage. The MPU
IC9003 of the D board is
used to detect and store
the history of abnormalities
that may be caused by a
defect in certain sections
of the unit. The input pins
of the MPU, as shown in
the figure on the right, are
used to detect possible
abnormalities. If one of the
protection circuits is
activated by some fault
within the receiver, the
problem facing the
technician is to find out
which protection circuit is
shutting down the receiver and why.
Figure 36
SOS Detect (DG Board)
The MPU IC4005 of the DG
board is used to detect and store
the history of other abnormalities
that may be caused by a defect in
certain sections of the unit. The
input pins of the MPU, as shown
in the figure on the right, are used
to detect possible abnormalities.
If one of the protection circuits is
activated by some fault within the
receiver, the problem facing the
technician is to find out which
protection circuit is shutting down
the receiver and why.
Figure 37
41
Summary of Contents for TH-42PX50U
Page 40: ...SC board Waveform Figure 30 SU And SD Board Shift Registers Figure 31 35 ...
Page 43: ...SS Board Schematic Figure 33 SS Board Waveform Figure 34 38 ...
Page 66: ...Adjustment Volume Locations Figure 53 61 ...
Page 67: ...Test Point Locations Figure 54 62 ...
Page 71: ...Scan and Sustain Drive Waveform Figure 55 Scan and Sustain Drive Check points Figure 56 66 ...
