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1.行不同步: 示波器检查:HA 11235行场扫描集成块(16)脚有行同步脉冲,说明故障不在Q703同步分离管。测量与同步脉冲有关的HA 11235各脚直流电压:(16)脚1.5 V,(12)脚6.8V均正常,而(14)脚3V(正常值6.8 V),(13)脚0 V(正常值3.6 V),断开C_(726)电容(0.15μ),(13)脚仍为0V。分析:因(13)脚无直流电压,则集成块内部BG13无偏置电压,其原因是BG16BE结断路,BG13、BG12均截止,BG11亦截止,故(14)脚电压也不正常。而BG12、BG13、BG15等组成鉴相器(乘法器),BG15B极送入同步信号,BG1、3B极送入行锯齿波,相
1. Line out of sync: Oscilloscope check: HA 11235 line scan block (16) has a line sync pulse, indicating that the fault is not in the Q703 sync splitter. Measure the DC pulse voltage of each pin of HA 11235 related to the synchronous pulse: (16) feet 1.5 V, (12) feet 6.8V are normal, and (14) feet 3V (normal 6.8 V), (13) feet 0 V Value of 3.6 V), disconnect C_ (726) capacitor (0.15μ), (13) is still 0V feet. Analysis: (13) no DC voltage, the BG13 no bias voltage within the block, the reason is BG16BE junction circuit, BG13, BG12 are cut-off, BG11 is also cut-off, so (14) voltage is not normal. The BG12, BG13, BG15 composed of phase detector (multiplier), BG15B pole into the synchronization signal, BG1, 3B pole into the line sawtooth, phase