Switching power supply maintenance detector

The utility model relates to a switching power supply maintenance detector, which comprises a detecting circuit and a pin jack connected with the detecting circuit. Three plugholes are arranged in the pin jack; the detecting circuit consists of a resistor R1, a resistor R2, a light emitting tube LED1, a switch K1 and a 9V direct-current power supply; a positive electrode of the 9V direct-current power supply is connected with the plughole 3 of the pin jack by the aid of the light emitting tube LED1 and the resistor R1 and connected with the plughole 1 of the pin jack by the aid of the switch K1 and the resistor R2; and a negative electrode of the 9V direct-current power supply is connected with the plughole 2 of the pin jack. When the switching power supply maintenance detector is used for detecting an LM431 parallel integrated regulator and an optical coupler, only pins of the parallel integrated regulator or the optical coupler need to be inserted into the pin jack, and then the light emitting tube is obser