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此故障在开机后半小时内图声都正常,半小时后无图无声(但有噪声)。当关机5分钟后再开机图声又正常,但只能持续5分钟,此故障又出现。因为有噪声,伴音通道出现此故障可能性要小,首先检查TA7607AP的各脚电压,见图。发现④脚无电压(14)脚电压为6V左右,此时分析的思路是:a)、先把AGC负载断开,(即插头拔下)测TA7607AP④脚仍无电压,此时测U_(R114)上两端电压接近12 V,测U_(R130)两端电压为0.1V,(正常工作时U_(R130)两端电压为OV)。b)、把R_(130)断开后,测TA7607AP④脚无电压,测R_(130)和④脚断开点为9.1V,此时说明AGC负载和
This fault within half an hour after boot tone sound are normal, no picture after half an hour silent (but noisy). When the power off after 5 minutes and then boot figure sound is normal, but only for 5 minutes, this fault appears again. Because there is noise, it is less likely that the audio channel has this fault. Check the voltage of each pin of TA7607AP first, see picture. Found that the voltage is not pin (14) pin voltage is about 6V, the idea of analysis at this time is: a), the first AGC load disconnected (that is, the plug unplugged) measured TA7607AP feet still no voltage, this time measuring U_ (R114 ) Voltage on both ends close to 12 V, measured U_ (R130) voltage across the 0.1V, (normal work U_ (R130) voltage across the OV). b), the R_ (130) is disconnected, measured TA7607AP pin no voltage, measured R_ (130) and ④ foot disconnect point 9.1V, this time AGC load and