Sharp LC-26GA4D Service Manual page 37

TROUBLE SHOOTING TABLE
<Signals>
No headphone audio output
YES
Check between pins (26), (27) (OUT L/R) of IC2702 and HP
AMP (IC2502), audio mute (Q2501) and headphone terminal
(J2402), as well as their peripheral circuits.
YES
Check the headphone plug circuit.
Check between headphone (pin (4) of J2402) and pin (7) of
IC1102.
No audio output during UHF/VHF reception
YES
Is the volume icon set on speaker when volume key is operated?
YES
Is there normal signal input at pins (67) (SOUND IF1) and (69)
(SOUND IF2) of IC2501 (Multi Sound Processor)?
YES
Are there normal audio outputs from pins (34) and (33) (SC2
OUT L/R) of IC2501 toward pins (32) and (33) of IC2702 (DIR)?
YES
Are there normal audio outputs at pins (28) and (29) (A-OUT
L/R) of IC2702?
YES
Are there normal audio outputs from pins (28) and (29) of IC2702
toward pins (13) and (15) of P3801 (1-bit amplifier input)?
YES
Are the 1-bit amplifier signals supplied to each pin of P8003?
YES
Is relay switching done normally from AV PWB P6003 to RY6001
(speaker switch)?
No Sound (1)
Check if monitor audio output is set to "variable" or if headphone
is connected.
Is there normal audio output in IC2501 (Multi Sound Processor)?
Check pins (37) and (36) (SC1 OUT L/R) of IC2501.
Check between pins (37), (36) (SC1 OUT L/R) of IC2501 (Multi
Sound Processor) and pins (5), (3) of IC2504 (EQ AMP).
Is there normal audio output for each?
Check between pins (5), (3) of IC2504 (EQ AMP) and pins (6),
(3) of monitor audio output terminal (J1105), namely Q1102 and
Q1103.
No Sound (2)
NO If monitor output is set to "variable" in the menu, change the
setting to "fixed".
NO Is there normal SIF output from tuner? (Pin (7) of TU1101 and
TU1102)
Check TU1101/1102 (U/V tuner) and the peripheral circuits.
NO
Check between pins (34), (33) (SC2 OUT L/R) of IC2501 and
pins (32), (33) of IC2702 DIR).
NO
Are there normal I/O signals of LRCK, BICK, SDTO and SDTI
between IC2702 and IC2700 (DSP)?
Check IC2702 and the peripheral circuits.
NO
Check the circuits from pins (28) and (29) of IC2702 to pins (13)
and (15) of P3801 (1-bit amplifier input), (IC3802 and Q3805-6).
NO
Check 1-bit amplifier and the peripheral circuits.
37
(Continued)
No monitor audio output
YES
YES
YES
YES
YES
YES
LC-26GA4D
LC-26GA4U