Patent ID: 8081212

Claim:
An abnormality detecting apparatus, comprising: a synchronous detecting circuit for detecting a synchronous signal from a video signal outputted from a video outputting unit; and path state judging means for judging whether or not a first direct current signal level obtained from an input path of said video signal is greater than a predetermined first threshold value, whether or not a second direct current signal level obtained from said input path of said video signal is smaller than a predetermined second threshold value, and whether or not said synchronous signal is detected by said synchronous detecting circuit, and determining that said input path of said video signal is in one of a normal state, an open state, a power connected state, and a ground connected state based on the result of the judgments, in which said path state judging means is operative to determine that said input path is in said open state when said first direct current signal level is smaller than said first threshold value, said second direct current signal level is greater than said second threshold value, and said synchronous signal is not detected by said synchronous detecting circuit.