Hello all,
This is my first time emailing the list, so please let me know if this doesn't belong here of if I'm breaking any rules.
A few months ago, I rescued a PDP 11/34a with 2 RL01 drives from the scrap heap. The unit appears to work fine based on my limited front-panel testing. I haven't gotten the drives running yet since someone cut the power cords when the cabinet was being removed.
There is a DL11-W serial line unit/realtime clock (M7856) installed in the 11/34 that I want to use for serial input/output. I have configured the card for 9600 baud, 8N1. Using some jumper wires, I carefully connected the card to a serial cable and a computer running a terminal and I was able to send some characters back and forth successfully.
For a more permanent solution, I designed a simple adapter board that connects to the BERG 40 connector on the DL11-W and converts it to a DB9 serial port (In restrospect, this product was already available at
https://oshpark.com/shared_projects/uTMf3v08 but I didn't know about that at the time). I also ordered a 40-pin (non-IDE) ribbon cable to connect the DL11-W to my adapter.
When I connected everything, the 11/34 would start but no lights would appear on the front panel. I tried disconnecting the adapter but leaving the ribbon cable plugged into the BERG connector, but the problem persisted. When I removed the ribbon cable entirely, the unit powered on with no problems.