LG RD-JT30 Service Manual page 34

JT31 Electrical Debug Guide
System no work
No
No data to
DDP1000
No
No im age
No
No im age when graphics
is the current input
No
No im age when video
is the current input
No
Unable to download
No
Unable to save
OSD setting
No
Yes
Keypad
m alfunction
No
No
Image crossover
distortion or contour
1.chk voltage input from DC/B : 3.3V(TP23),5V(TP24),12V(TP34)
2.chk oscillator Y4,Y5 output frequency (Y4:16.257MHz, Y5:10MHz))
3.chk MCLK(U37-5,130MHz) and DCLK(U39-5,40MHz)
4.chk U38 whether S/W inside or bad soldering
5.chk Reset IC (U40)
6. change U35(bad soldering)
Yes
7.chk Abnorm al signal
8.chk Resetz(RN40),PW RGO OD(RN40) ,VSYNCZ(R182), HSYNCZ(R183),
ACTDAT A(R184), CLKIN(R181)
1.chk output from U32(RN16-RN21) [graphics input]
2.chk output from U109 (RN101 - RN104) [video input]
Yes
3.chk U1and its peripherals (as above block)
1.chk DDP1000 debug guide
Yes
1.chk D_SUB cable and J103
2.chk VSYNC(U103-4),HSYNC(U105-4)
3.chk U32 voltage source U29-2(3.3V),U30-2(3.3V),L22(3.3V)
Yes
4.chk G HS1(R171), GVS1(R170), GCLK(R173)
5.chk U3 2soldering
6.change U32
1.chk video input connector J12 and J102
2.chk U107 voltage source L110(5V), L111(3.3V),VSTBY(U107-59)
3.chk Y101 output frequency(20.25MHz)
Yes 4.chk U107 output signals to U109 (Y0~Y7, UV0~UV7)
5.chk U107 soldering
6.chagne U107
1.chk U20 enable pins(1,4)
Yes
2.change U20
Yes
1.change U41
1.chk R103~R106 soldering
2.chk U18(74AHC244)
1.chk soldering from RN16~RN21 (graphics input)
Yes
2.chk slodering from RN101~RN104 (video input)
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