Read LG 19LV2300 (CHASSIS:LA86D) Service Manual online
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A SMPTE Color bar signal is recommended for this
trouble shooting(1920*1080/59.934Hz).
Since the waveform of the RGB input is logical, you
may use any pattern.
Check JK705. .(pin no. 1(R)/2(G)/3(B)
Can you see the normal waveform?
Refer to figure 1
JK705 may have problem.
Replace this Jack.
These points art applied connonly about all video input.
Check the input (Pin AK16,AN15,AM15,AH16,AJ16)of
BCM355x(IC100).
Measure waveform at C635,C636,C637 and R755,R758 because
it
’s more easy to check.
Can you see the normal waveform? Refer to figure 1
RGB PC-VIDEO
YES
YES
Figure 1
YES
NO
NO
Check all power domain of MT8280FG (IC1000)
(MT8280_CORE_1.0V,MT8280_DVDD33,MT8280_AV33,
AVDD12,AVDD12_SYSPLL,AVDD12_DMPLL,
AVDD12_MJCPLL,MT8280_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?
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.
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)
Figure 2
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