TIVO Series 4 Premiere Power Supply for Models TCD746320, TCD746500, and TCD748000. Board # ST8015. This was tested under a load in a working TiVo unit by a qualified technician. Each board was under test for at least 1 hour to verify it worked under normal operating temperature. Since I cannot test your individual TiVo to verify your power supply is indeed the cause of your problem, I cannot guarantee this replacement power supply will repair your non functional TiVo. You will need to verify that either your board’s fuse is open, or that your board is not putting out the correct voltages. This item is being sold as is.