It was not completely random - I have started with single power-on key presses.? Only found that "Local" starts up HP-IB debugger.
Then, after going through service manual yet again I have noticed that, apparently, "The fault log can be displayed at power-up by pressing and holding [.] [4] while setting the power switch to on"? This, obviously, did not work but I know what you are thinking - why [4]?
So I set off to try everything else together with [.] and got lucky pretty much instantly.
Of course, restrospectively anything can be found on the Internet -
I took all the cards out, replaced the battery (which was at 0.6V) and blew the dust off them.? So NVRAM probably got rubbish stuck in it that crashed bootup very early on.
Why HP did not document this in the service manual - I have no idea.
Cheers
Leo
