Open chassis, visual observation, found no problem with multimeter electric block several key parts of the measurement are problematic, found that the manager has breakdown short circuit. Carefully detect circuit, in addition to a few place is not obvious on the boards of virtual welding, found no other components damaged, that is virtual welding pipe damage, then replace a manager after the boot instantly hear the sound of the high voltage start, then immediately disappear, measuring just change to pipe damage again. SbWservice manual download site
 SbWservice manual download site
To determine exactly what causes line camp breakdown, adjust the resolution of the host for the 640 x 48 o, for 60 hz refresh rate adjustment, change the line camp after the secondary power booster tube Q402 will be removed, boot grating appeared, the screen shows the basic normal, demonstrating basic normal line output circuit, the fault should be the secondary power supply circuit work out of control and results in excessive booster and over-voltage breakdown line camp. SbWservice manual download site
 SbWservice manual download site
 SbWservice manual download site
Through the analysis of the secondary power supply to power supply voltage rise, prove the booster circuit basic normal, problem should be caused by the secondary power supply voltage regulator circuit work properly. The machine USES the line oscillation chip is STV9118, internal integration regulating circuit, through its (15) feet of the secondary power sampling (as shown), within the integrated block is calculated after processing, from 28 feet output control - DRV B signal to control the working state of the booster circuit, voltage regulator. Boot at the ends of the measuring C533 voltage is very low, normal should be about 25 v, when measuring the road which the various components, found no problem. C533 will be removed to measure, found that the charge and discharge rate, with a new 200 uf capacitance change / 50 v, C533 voltage on both ends for 23 v. To recover back into Q402 circuit switched on grating, switching various resolution is no problem, troubleshooting.

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