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[例1]故障现象 图像左右均向内凹,其它均正常。 分析与检修 拆卸机后盖观察机内元件,发现在行输出变压器附近直立的枕校电路板上六只相同的电感LJ10～LJ06几乎全部断裂,但在维修中发现,更换新的LJ01～LJ06后虽能正常工作,但往往使用不久又会重复上述故障。笔者利用如下方法进行了改进,收到了满意效果:(1)改CJ02(6800pF)为0.01μF;CJ05(0.1μF)为0.01μF;CJ06(5600pF)为2400pF;RJ13(680Ω)短接;RJ14(4.7kΩ)短接;RJ18(47kΩ)为24kΩ;RJ22(22kΩ)为18kΩ;RJ21(15kΩ)为1.5kΩ;RPJ03(200kΩ)为150kΩ。(2)在TDA8145的⑤、⑥脚之间接一只1N4148型二极管,其负极接⑥脚。(3)上述改动无误后可开机试验,若产生自激(垂直线条呈锯齿状),可适当减小电容CJ06的值,直至自激消除为止。 [例2]故障现象 图像很暗,调大亮度时图像、彩色反转并有严重拖尾现象。伴音正常。
[Example 1] Symptom Images are concave to the left and right, the rest are normal. Analysis and maintenance Demolition machine back cover to observe the machine components found in the line output transformer near the upright pillow school circuit board six identical LJ10 ~ LJ06 almost the same fracture, but in the repair found that after the replacement of the new LJ01 ~ LJ06 Although it can work normally, but often will soon be repeated use of these failures. The author uses the following methods were improved, and received satisfactory results: (1) to CJ02 (6800pF) of 0.01μF; CJ05 (0.1μF) of 0.01μF; CJ06 (5600pF) of 2400pF; RJ13 4.7kΩ); RJ18 (47kΩ) is 24kΩ; RJ22 (22kΩ) is 18kΩ; RJ21 (15kΩ) is 1.5kΩ; RPJ03 (200kΩ) is 150kΩ. (2) Connect a 1N4148 diode between the ⑤ and ⑥ pins of TDA8145, and connect the cathode to ⑥ pin. (3) After the above changes can be boot tested, if the self-excited (vertical lines were jagged), may be appropriate to reduce the value of the capacitor CJ06 until the exclusion of the exclusion. [Example 2] Symptom The image is very dark, the image brightness increase, the color reversal and severe tailing phenomenon. Sounds normal.