Roe
Experienced Member
Greetings. I'm a newbie here, but I started working on pdp11 systems in 1974, I'm resurrecting an 11/34a, and I'm hoping the crowd can help me with a strange problem.
The 34 boots, front panel works, memory seems to work, ctrl/boot starts the bootstrap rom on the system console. I can manipulate memory from the front panel, and the console, no problem at all.
Here's the problem: if I enter a dead simple program from the front panel, say 000777 at mem location 1000, load address 1000, and hit ctrl/start, the system seems to start and then halts immediately. If I then use ctrl/cont, the system starts running. In other words, ctrl/start just isn't starting the system.
If I attempt to use the boot rom "S" command to start the system , for example
L 1000
D 777
L 1000
S
Things get strange. I get a junk character on the screen, the system seems to be running, but any attempt to use ctrl/halt from the front panel causes a BUS ERR light, the RUN light stays lit, and I cannot regain front panel control at all. I have to power off the system to regain control.
Does this sound familiar to anyone?
Thanks.
The 34 boots, front panel works, memory seems to work, ctrl/boot starts the bootstrap rom on the system console. I can manipulate memory from the front panel, and the console, no problem at all.
Here's the problem: if I enter a dead simple program from the front panel, say 000777 at mem location 1000, load address 1000, and hit ctrl/start, the system seems to start and then halts immediately. If I then use ctrl/cont, the system starts running. In other words, ctrl/start just isn't starting the system.
If I attempt to use the boot rom "S" command to start the system , for example
L 1000
D 777
L 1000
S
Things get strange. I get a junk character on the screen, the system seems to be running, but any attempt to use ctrl/halt from the front panel causes a BUS ERR light, the RUN light stays lit, and I cannot regain front panel control at all. I have to power off the system to regain control.
Does this sound familiar to anyone?
Thanks.