Instant boot sound high pressure created, and then three non-measuring Q841 and Q554 base has 0.7V voltage to determine the protection circuit is activated.TBWservice manual download site

     Voltage measuring method using the repair. Instantaneous power measurement of a, b, c, e, f, g test point voltage, f is high instantaneous power point, the output circuit determines the presence of faults. The output circuit for field testing, found that farm output circuit IC451 (LA7838) internal short circuit. After replacing IC451, the boot is no longer protected.TBWservice manual download site