Ok, your system is not reading your System Monitor (IOD300). What type of circuit card is connected to your System Monitor? Is is a 2 or 4 port paddle board. (After Release 25 you should be using a 4 port paddle board as the 2-port was MD and is not supported on the Succession Line) You may need to change this out as well as your system monitor to clear these issues. The system monitor is the lovely little card that controls the power functions in the column and can take a column down fast.
Here's what I would do:
1. disable your system monitor (dis tty 0)
2. disable all TTY ports on the paddle board, flip the toggle switch, pray you don't shake the card wrong and reseat the card. Any tech on here will tell you that if you rattle that card wrong trying to get it in or out can reset the switch.
3. Reseat the System Monitor card. While it is out make sure you are have the correct dip switch settings. Also to be a real stickler what is the vintage of System Monitor Card you are using? No AA, but AB to AD are supported. Without the AD, just remember your little Nortel blue light won't work.
4. Put the system monitor card back in
5. throw the toggle switch on your paddle board back to enable
6. enable all your tty ports on the card
7. do a stat xsm and see if you get any PWR messages
All PWR messages will be good because at least you are seeing your System Monitor chain.
But....
PWR000 = good message
PWR(anything else) No Bueno, especially the dreaded PWR007.
This should get you there. Now you can do this during business hours because the NTPs tell you how to do this without it being service affecting, BUT I would do it after hours. (I don't trust anyone)
Hope this helps. I just did this process last night for the same IOD message. customer had 2-port paddle board and bad System Monitor.
Also remember to have a secondary access point to the switch (J21 or J25) in case your terminal is on the Paddle board.
Hope this helps.
John