关于山特UPS-TG500

有一台山特UPS-TG500见图,不知是山特的哪一种版本哪个厂家生产,没有原理图(找过多份图纸都不符)
故障是可充电、可逆变、就是不能用市电,请专业人士指点.
先在此谢过!
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