I recently purchased a Juniper J2320 from eBay for a fair price. I know it is an older router, but it has the features I need in order to test and write a few things. When I received the router it was not sent with a wiped config, so I was unable to log into it upon booting.
Since I need to recover the device, figured might as well write and share how to do it!
Obviously the first thing you will need will be a Serial connection to the device. I am assuming you have a USB -> Serial adapter, if not this is the one I have and I got it from Amazon here LINK.
1. Make sure the power to the device is turned off. If it is turned on, please use the power button to force the system to shut down cleanly. If you do not do this and just yank the power, you risk corrupting the OS and having more fun later.