Plug the Cable from your laptop into the 25-pin port that should be on the right side of the Custom Callout Adapter. That will get you a unix login prompt using 115200, 8, N, 1.
The tech use Comwin to access 9006, but I have never done it before. I'm kind of a rookie at Comwin and I still have to fire it up using the assistant on HiPath 4000. I can run it, but I don't know how to kick off the connection process. I assume you would create a new serial connection using the above COM parameters and whatever serial port you have the cable connected to, and then tell it to connect. I don't think when you use Comwin that you have to worry about the keyboard mapping files you need for Procomm. If it's a 30EP the best way to administer it with LC-Win software. Usually they will leave the install CD inside the cabinet - unless your people moved it.
I can't help you with your password for the rsca login - that is usually left up to the vendor that installs the system. If you happen to be in WI and have Norstan/BlackBox as your vendor I could give you an educated guess, but otherwise I can't. You can try using "password1" (that is a numeral one) which is sometimes used by techs as a temporary password when it makes you change it - until you can login and change it back to what it was.
If there is anyone else there that used to administer it on your company's behalf there might also be a customer login set up for you, and manybe there are notes about it.
If you have a 2 cabinet system, and you have NO Analog cards installed in the second cabinet, you probably could swap the power supplies between the two cabinets and it will probably fix the problem. I have a lot of spare parts, but I don't have one of those power supplies, and I wasn't about to spend $1000 to buy one just to troubleshoot a problem!
Good luck!