I have been given a Jensen (I believe aka DECpc AXP 150). I am told that the
machine worked when last used, but I am unable to get even to the console.
Here is what I have tried:

First I connected a VRT17 monitor and a keyboard (actually a PC one rather
than an LK411 as I did not have an LK411 at that time). Nothing appeared on
the screen.

Then I switched to trying to get the console to work on a terminal, I have a
VT420 (set to 9600,N,8,1). I connected this to both of the 9-pin serial
ports (cycling the power each time). Nothing. I also tried connecting it to
the 25-pin printer port, still no luck. My breakout box does not show any
activity on the 9-pin serial ports.

There are 4 diagnostic lights on the back, they are all on and red.

I have been unable to find any documentation on the web.

Any suggestions what to do next?