Sharp 4T-B70CJ1U Service Manual page 29

2. HOW TO RESPOND BY TROUBLE SYMPTOM (IN CASE OF DEFECTIVEMODE)
No
1 No Power (front LED failure to light up) or no startup (front LED failure to turn red to green)
2 With [RF]signalinput No video onscreen(1)
3 With <Video>signalinput No video onscreen(2)
4 With <HDMI1/HDMI2>signalinput
5 No audio heard (1)
6 No audio heard (2)
7 No audio heard (3)
2-1. No Power (front LED failure to light up)
or no startup (front LED failure to turn red to green)
Are the wire harnesses and other cables properly
connected in the set?
↓ Yes
Are the PS_ON and PANEL_EN signals both
about 3.3V?
PS_ON:Q9607(G), PNL_EN:Q3803(G)[60"/70"]
Q3802(G)[80"]
↓ Yes
Are the DC/DC converter outputs and the output voltages
along the control lines as specified?
1) D5.1V_USB (IC9607)
2) D3.3V (IC9605)
3) D1.8V (IC9601)
4) CPU D1.0V (IC9604)
5) CORE D1.0V (IC9603)
6) D1.5V (IC9608)
7) BU+5V (IC9610)
8) BU+3.3V (IC9605)
9) BU1.0V (IC9609)
10) PNL+12V (60"/70":Q3804, 80":Q3801)
2-2. With [RF]signalinput No video onscreen(1)
No video in the UHF/VHF reception
↓ Yes
Is there IF output from the tuner
pin(6,7,8,9) of TU1102 as specified ?
↓ Yes
Is there IF input at pin K1 & K2 of IC3301 ?
↓ Yes
Are there the signal outputs (pin of IC3301
to SC 3801) ?
↓ Yes
Check FFC cable, LCD controller (incl.
panel) and their peripheral circuits.
No video onscreen(3)
4T-B70CJ1 TROUBLE SHOOTING
Description
Reconnect the wire harnesses and other cables
NO
properly in the set.
Check the PS_ON and PANEL_EN signal line.
NO
Check the DC/DC converters and the
NO
control lines. Replace defective parts as
required.
Check TU1102 and its peripheral circuits.
NO
Check the circuit between TU1102 &
NO
IC3301.
Check IC3301 and its peripheral circuit to
NO
SC3801
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