Baydel STBC (B01076) & ROI MRL-11

[Jager]

Greetings.
I've came across several non-DEC PDP-11 boards, and I couldn't find information about these two. ROI MRL-11 should be pretty straight-forward 1 meg of RAM, but any additional info will be helpful.
Baydel STBC (B01076) jumpers/switches, on the other hand, are way harder to decipher. It also has "Boot rom revision level 2.4" ROMs - is there anything better, preferably with net boot?

 

[Jager]

So far I've discovered by poking around:
ROI MRL-11 - M/QM jumper limits RAM to 256k?, WP does something to parity, but it passes various memory tests anyway.
Baydel STBC - SW2 - console settings, 1-4 - parity, data bits, stop bits, 5-8 - baud rate. SW1-3 for some reason messes up PDP11GUI ability to examine/deposit, it types weird symbols instead, SW1-5 disables ROM page register (177520), SW-7 disables ROMs, SW1-8 disables console port. The ROM page register seems to be BDV11-compatible.

 

[Radix]

Hi - Many thanks for sharing the Baydel ROMs - they work in a BDV-11 board, when split into 2KB chips and should be a pretty good bootstrap - I have been looking for a copy for ages...

There may be newer versions if there are not many options...

The STBC board is Serial, Terminator, Bootstrap and Console (1 x DL port) the other connector is for the front panel switches - and the 3 pin connector is for about 6v AC for LTC and power fail detection...

I should have some switch and jumper information for the board - I'll have a look tomorrow...

Robin

 

[Radix]

Ah - Found it... my notes for the other engineers from 1989...

Baydel were a supplier of ours and we worked closely with them

Robin

 

[Jager]

Awesome, thanks.
Do you remember how front panel looked like for this board? Probably just 5 switches (LTC, INIT, HALT, ???) & 3 LEDs (RUN, LTC, DCOK?), since board has UA9667 connected to J1, presumably to drive LEDs directly.

 

[Radix]

Hi - I actually have an earlier version of a Baydel PDP-11 - the front panel layout is the same as the later systems, but I don't have the wiring for the 10 way connector, sorry..

But I am fairly sure there were no other components on the front panel - just the switches and LEDs.

The power switch was a key-switch but it looked very easy/likely to snap off the key, so I changed it to a rotary mains switch as you can see in the photo - the mains switch wiring goes directly to the PSU, etc.

Robin