Check the jumpers on your CPU card, jumper W8 if in will set the system starting address to 173000 where the boot strap stuff will be. If that’s out the system will start on whatever combination of jumpers are installed in W9 to W15. If you have the BDV11 bootstrap terminator card that will have the ROM for booting from any of the DEC devices like the RL, RX or TU-58 drives and the system will great you with a friendly START prompt and when you enter nothing or a wrong input the system will dump you back in ODT. The KDF11-AA user guide is your friend!