The phenomenon of BGA (IC057) bad. 8KNservice manual download site
Measurement of BGA power supply is normal, check the peripheral exclusion devices such as did not see abnormalities. Gently tap on a circuit board, occasionally can be normal. 8KNservice manual download site
After the test, to confirm this phenomenon for welding or poor contact, careful testing IC057 welding and its surrounding components, found X4002 virtual welding, returned to normal after repair welding images. 8KNservice manual download site
Use for a considerable time machines, some failure may be caused by solder joints virtual welding, so the appropriate tap on a vibration helps to find root causes.8KNservice manual download site