GX520, PSU compatibility

Please do You know if BTX power source 0KC672  used in Dell GX520 Desktop  is pin/electricaly compatible with standard ATX  power source ?  Before buying replacement I would like to try startup PC with ATX power source. Actually PC do not went to POST, just fans are spining. 12 V rails has only 11.44 V with HDD and DVD disconnected. There is no adtional PCI card instaled. LED is solid Orange.