Northstar Single Density Controller info MDC-A4

Hi all, I have put my Intel MDS system on hold while I await some hardware information in the mail. I am resurrecting the second half of my project which is to get a Northstar system up and running so I can develop the ISIS-II code again. The problem I have at the moment is that I need the schematics for the MDC-A4 controller. I have two manuals on the double density controller but nothing on the one I am using. Does anyone have the manual available with troubleshooting info or at least the schematics. I am more than willing to scan docs I have in trade. I am off troubleshooting the controller because it will not write properly. I can load a fresh copy of DOS, customize the I/O and actually run DOS now, but I can't update and make a new copy because of the write issue. I did manage to fix an Applied Microsystems EM180B Z80B emulator today so I could enter the console code and run things. Thanks! best regards, Steve Thatcher