This page documents the steps taken to “upgrade” the ROMs in a standard BDV11 in August 2018.
This BDV11 had only two ROMs in it. They were marked U49 and U54. They were in the locations that I later replaced with 453-1 and 454-1 respectively.
The original ROMs used to conduct a Memory Test and then give a “Start?” prompt. I did limited testing of these original ROMs, but can confirm the entering DD0 or DL1 at this prompt booted TU58 Unit 0 or RL02 Unit 1 respectively.
The original 8-way dipswitch setting was (1-8): 11010010
The original 5-way dipswitch setting was (1-5): 00000 on the first board, and 00001 on the second board
I fitted ROMs 453-1 to 453-4 and 454-1 to 454-4.
The new dipsw setting were:
8-way (1-8): 00000011
5-way (1-5): 00000
The conversation worked great. It greeted me with the following:
KDF11B-BJ ROM V1.1
Apart from the change in dipswitch settings, no changes were required to the BDV11 board.
On some boards, you will see 4 wire links that have been added to Pins BC1-BF1 in the lower-right corner of the PCB. This is to allow the BDV11 to work in a 22-bit backplane. This ECO is documented in the BV!!-A Maintenance Print Set (see below for link).
Resources
The best resource for technical information about the BDV11 is the “LSI-11 Systems Service Manual, Volume II” at page 425. The DEC Part Number for this manuals is EK-LSIFS-SV-005. I have extracted the BDV11 pages from this manual and they can be downloaded here -> BDV11 extract from LSI-11 System Service Manual. This extract has information about dipswitch settings, LED status indicators, jumper settings, memory map options, and halt addresses. It doesn’t provide the ROM-socket designators, except for the originally fitted ROMs.
Also useful is the BDV11-A Field Maintenance Print Set, DEC Print Set Order No. MP00489. This has the full circuit diagram, component locations, and other useful information.
I have previously published a webpage with more details about installing the PDP-11/23+ (KDF11-B) ROMs in the BDV11. This is useful because it provides many boot boot-device options, as well as an interactive boot menu. Unfortunately this only works with the PDP-11/23 (M8186) and won’t work with a PSP-11/03 or PDP-11/53, though there are some work-arounds (disabling memory tests etc) which apparently increase compatibility with other processors. I haven’t yet experminted with this. This webpage is no longer available online, but is available here on the Wayback Machine.