After opening the test machine, and so failure to detect, but the fault has been not appear, it is relatively difficult to repair large heated board with a hair dryer, the same is not a failure, and then close the cover, with a wire from the IC1213 (33) foot, i.e. the end RELAY lead to measurement. Found that when the foot is reduced by the failure of normal 5V 0V, so it's only based on the phenomenon should be checked empirically computer circuit blocks and related working conditions, combined with the substitution maintenance,

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