Sharp LC-46X8E/S/RU, Service Manual

Page: 50 / 166

LC-46X8E/S/RU
4 – 10
No picture on the display (3)
The picture doesn’t come out when DTV is received.
TERMINAL UNIT:
Is the regulated power supplied to TUNER (5V/5VCONT) and
IC7507 (B3.3V/B1.8V)?
NO Each power supply circuit is checked.
YES
Is IF signal output from pins (20, 21) of TUNER (TU7501) to pins
(30, 31) of IC7507 (COFDM)? NO Check the tuner, IC7507 and their peripheral circuits.
Replace as required.
TERMINAL UNIT: YES
Does serial control signal (SDA/SCL) operate with pins (15, 14)
of TUNER and pins (5, 4) of IC7507? NO
YES
Does X7502 (20.48MHz) of IC7507 oscillate? NO Check X7502 and its peripheral circuits.
YES
Is MPEG data (FECLK/FED_D/FESTR_PSYNC/FEVAL_DEN)
from IC7507 output to pins (1, 3) of connector (P7501) and pins
(51, 50) of connector (SC501)? NO Is the control signal named IC7507 and IC9101 (CPLD) normal?
(FE_RST_LINE, FEERR_LINE, FEPG0_COMP_LINE,
FEPG1_LOCK_LINE, etc.)
MAIN UNIT: YES
Is the digital signal (FECLK/FED_D/FESTR_PSYNC/
FEVAL_DEN) sent to pins (1, 3) of connector (P1103) and pins
(51, 50) of connector (SC1101)? NO Check connector (SC501/SC1101 and P7501/P1103).
YES
Is the digital signal (FECLK/FED_D/FESTR_PSYNC/
FEVAL_DEN) input to pins (AF3, AF2, AF4, AH3) of IC8101
(CPU/DECODER)? NO Check the line between SC1101,P1103 and IC8101.
YES
Does X8101 (24.00MHz)/X8102 (32.768kMHz) of IC8101 oscil-
late? NO Check the X8101/ X8102 and their peripheral circuits.
YES
Are video signal (VDB_R [0:9], VDB_G [0:9], VDB_B [0:9], and
VBD_CLK/DE/HD/VD) are output from IC8101 to IC3301 (VIDEO
PROCESSOR)? NO Check IC8101, IC3301 and their peripheral circuits.
(IC8301-IC8304 (DDR2_SDRAM), etc.)
YES
Refer to “The picture doesn't appear in all modes.”