Character display normal without sound, fault generally involves the entire audio system, and to work into the circuit damage. On checking power amplifier circuit IC201 (AN5265) and its peripheral components without exception, but the volume control the input voltage of 0 v, (4) feet of control circuit is abnormal. fPaservice manual download site
 fPaservice manual download site
Press the "+" or "-" volume key, measuring the appended drawings of the CPU (1515), the volume control of output voltage change is normal, 16 feet Q1102 b normal voltage changes, its e a 12 v power supply is normal, but no voltage, e check Q1102 was not damaged. Measurement noise control CPU side pet-name ruby foot constant voltage of 5 v, presence of signals are. fPaservice manual download site
 fPaservice manual download site
According to the measurement result analysis, no audio fault is obviously CPU pet-name ruby feet at a high potential to cause, because pet-name ruby high potential for feet, make Q1103 conduction, will Q1102e on clamping voltage of 0 v. Try to CPU pet-name ruby feet and sub, voltage to artificially reduce the foot, but in the short answer is automatically turned off. Judge CPU pet-name ruby foot inside and 5 v power supply side short circuit, causing the CPU power can't work, caused to turn it off. In measuring the CPU pet-name ruby feet and resistance of power supply pin is akin to 0 Ω, confirm the above right. To fix the problem, of course, it is best to change the CPU. Considering the CPU only mute pin failure, in order to reduce the maintenance cost, obtained the consent of the owner's, the author USES the methods of emergency treatment, the resistance of R1149 cancelled in CPU pet-name ruby feet can. So will not work related noise circuit, only the volume control circuit to work, only in the absence of signal and noise in the transformation channel instantaneous, but does not affect the normal watch.fPaservice manual download site