TMA-11/TS03

With the help of various knowledgeable people on this list, it was pointed out that I did not have the connection to the tape drive controller in the correct position. To test the tape drive, I used the programmer's console on my PDP-11/05 to issue a read command to a mounted tape. When I issued a read command by depositing a command into the TMA-11 command register, the tape advanced slightly and then stopped. The 'Bus Grant Late' error was set in the TMA-11 status register. The status register did indicate the controller and tape drive were both ready. No data was read in. The read command was issued while the processor is halted. This particular system did not originally have any external devices hooked up to it. Beginning at the processor, the system has the following components installed: KD11-B PDP-11/05 LS11 line printer card (connects to a Centronics 101A printer) MM11-U 16K x 16 core memory MM11-U 16K x 16 core memory RK11-D RK05 disk controller (See http://www.iamvirtual.ca/collection/systems/minis/PDP11-10/Boards.html for details) The BC11 cable leading to the TMA-11 controller is put on the Unibus out connection at the last slot of the RK11-D controller. Based on previous posts from others, I suspect I don't have the processor grant set up correctly. I am currently reading several different manuals to get a description of how the grant lines should be hooked up. I have read many descriptions of the signalling, but I have not located information on where to use the Grant Continuity cards or making changes to the wire-wrapped bus. In my case, I will need to make changes to the bus, since I do not have any of the Grant Continuity cards ;-) Am I on the right track to assume that the problem is likely to be the processor grant wiring, or should I be looking elsewhere? Many thanks for any pointers! --barrym