Read LG 19LV2300 (CHASSIS:LA86D) Service Manual online
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Check TU1 Pin16(Video output)
Can you see the normal signal?
Could you measure voltage
of TU1 & IIC lines?
Are they all normal?
You should replace TUNER.
You should check power line & IIC lines.
5V should be on for the voltage.
Check the input(Pin1)
of LPF(IC808).
Can you see the normal waveform?
Check the output(Pin8)
of LPF(IC808).
Can you see the normal waveform?
After checking video signal line & the Power of LPF you should decide to
replace item or not.
After checking the Power of LPF you should decide to replace LPF or not.
These points art applied connonly about all video input.
No or poor signal replace what? No or low voltage check where next?
If no or poor signal or low voltage shows up, you may be able to
suspect IC808 or adjacent resistors or capacitors.
This board has big problem because Main chip(BCM3553) have some
troubles.After checking thoroughly all path once again, You should decide
to replace BCM3553 or not.
Check the input(PinAN16) of BCM3553(IC100).
Measure waveform at C658 because it
’s more easy to check.
Can you see the normal waveform?
This board has big problem because FRC chip(MT8280FG) have
some troubles.
After checking thoroughly all path once again, You should decide
to replace FRC-9459M.
Although you replace it, you cannot see normal display, decide to
replace Main chip(BCM3553)
Check all power domain of MT8280FG (IC1000)
(MT8280_CORE_1.0V,MT8280_DVDD33,MT8280_AV33,AVDD1
2,AVDD12_SYSPLL,AVDD12_DMPLL,AVDD12_MJCPLL,MT828
0_DDRV) & crystal output (X1200 / 27MHz) & FRC_RESET
Measure Power & waveform at C1224, L1207, L1208, C2213,
C1236, L1209~L1211& C1290 & R410 because it
’s more easy to
check.
Can you see the normal waveform?
TV/CATV-VIDEO
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
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