Test apparatus and diagnosis method

A test apparatus that tests a device under test, comprising:

• a plurality of modules that each include:
• a plurality of channels that each have an output circuit that outputs a prescribed output signal to the device under test and a measurement circuit that measures a prescribed characteristic of the device under test;
• a load resistor;
• and
• switches that each connect the load resistor to an output end of the output circuit and to an input end of the measurement circuit of a corresponding channel under measurement from among the plurality of channels, the test apparatus further comprising
• a control section, provided in common to the plurality of modules, that causes the measurement circuit in each module to measure output of the corresponding output circuit, sequentially reads a measurement result of the measurement circuit in each module, and diagnoses each module by (i) calculating an ideal value to be measured by the measurement circuit based on a setting value of the output signal output by the output circuit and a resistance value of the load resistor and (ii) comparing a measurement value measured by the measurement circuit to the ideal value, wherein
• measurement of the output signal of each output circuit by the corresponding measurement circuit is performed in parallel for the plurality of modules, and
• when diagnosis is completed for the channel under measurement in each module, the control section controls the switches in each module to select the next channel to be diagnosed, measures the output of each output circuit in the selected channels in parallel, and sequentially reads the measurement result of each channel to diagnose the channel.