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4-6
SHORT Detect
The short Detect circuitry is shown in Figure 4-6 and is
the same as in the V19 and V21 chassis. If a short
occurs in the + or – 24V supplies, pin 46 on IC7A00
goes Low indicating a short and the TV shuts Off. With
-24V shorted, the 12VS supply turns Q9A53 On, pull-
ing the SHORT line Low. If +24V is shorted D9A54 is
forward biased and the short line goes Low.
X-RAY Protect
Refer to Figure 4-7, the X-Ray input is at pin 47 of
IC7A00, and is normally High. The X-Ray Protect
circuit monitors:
• Excessive HV
• Excess CRT Beam Current
• Excess HV circuit Current
If any of the preceeding occurs, the X-Ray line goes
Low, and the TV shuts Off.
The monitoring circuits for X-ray Protect are described
in the detail in the Deflection and HV Section. Other
parallel inputs to the µPC, are listed in Table 4-1.
IC7A00 Additional Inputs
Pin #
Name
Source
6 SD-SUB Sub Tuner Sync Detector
7 SD-MAIN Main Tuner Sync Detector
62 H-SYNC-IN ASIC Horizontal Sync
64 V-SYNC-IN ASIC Vertical Sync
92 AFT1 Main Tuner AFT voltage.
93 AFT2 Sub Tuner AFT voltage
94 VBLK Deflection Loss Detect circuit
97 CV-IN-SUB Sub Video (CCD, V-chip,etc)
100
CV-IN-MAIN
Main Video (CCD, V-chip,etc)
Table 4-1: µPC Inputs