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Panasonic TC-29GF80R TV without gratings, no sound, no fault repair method of character

Time：2014-07-05 08:12:04 Source：Network Author：Unknown Clicks：1292

The organ machine screen shining, line scan circuit basic normal work, try to improve the accelerating voltage, screen appears to sweep line grating. And can see very light image contour line. PwAservice manual download site
PwAservice manual download site
According to this phenomenon, first detection IC3501 (TDA6103Q) feet voltage (as shown), found that the R, G, B signals input end (1) - (3) feet only 1.5 V voltage, normal should be 1.9 V. Proceed to check IC3401 (12), (14), (16) foot (R, G, B) voltage output is 19 V, 1.9 V, 1.8 V respectively, the normal is 3.6 V, 3.5 V, 3.5 V. (5) measuring foot 12 v power supply voltage is normal. Continue to measure IC3401 (TA8889AP) R, G, B type foot (1), (3), (6) feet voltage 1.6 V, 1.5 V, 1.5 V (normal value of 35 V, 3.4 V, 3.5 V), suspected of the front-end circuit has a problem, then check IC601 (60) feet (Y) signal input end voltage, normal. PwAservice manual download site
PwAservice manual download site
PwAservice manual download site
With an oscilloscope measurement IC601 (60) feet waveform is also normal. PwAservice manual download site
PwAservice manual download site
The detection signal has been into Ic601, but Ic601 (16) ~ (18) foot (R, G, B signals output) without output. So focus on testing Ic601. Measuring the (19) and (36), (50), (59) foot (power input) voltage is 9 v. Normal; (25) foot (zero point) voltage is normal; (14) foot (serial clock signal) voltage 4.9 V, normal; (13) foot () serial data signal voltage at around 1 V, and the normal value of 4.8 V now finally found the problem. PwAservice manual download site
PwAservice manual download site
IC601 (13) with foot IC1213 (28) feet. Measured ICl213 voltage of 4.8 V (28) foot, normal, visible in this section of the line. After inspection found that the double sided PCB hole impassability. Serial data not to IC601, IC2401 integrated block, the multiple integration block doesn't work, so no grating, no sound, no dark grating fault display of characters. Through to the line after the commissioning, troubleshooting. PwAservice manual download site
PwAservice manual download site
Note: due to the double sided PCB via joint copper foil thinner narrow. Corrosion cracking of vulnerable to contamination, so when maintenance should be paid attention to test it on and off.

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