Thanks Tony_G, appreciate the thoughts!
I’ve since done a bit of research and that does appear to be the case with the “kernel”. Best I can tell so far, the operating system is not setting up the RAM chips to get things started on power up, as it’s supposed to do.
After pecking through the troubleshooting tree I think I’ve come to a, let’s just say “pause point”. It’s telling me to “fix the kernel” via setup 2.1. (See attached pic) I also attached a pic of the screen after removing jumper P410. The whole screen then filled with little question mark symbols, which I took to be the “blanks” described in the tree.
A number of questions to think about at this point, and I don’t have a functioning analyzer to test the over 30 pins that reveal the operation of the “kernel” per the prescribed procedure. I suppose this is why they refer to the error code “3,4” as a fatal error! Replacing the RAM in this guy must involve more than sticking new chips in. There’s no procedure for replacing the RAM outlined in the manual, only which pins to test on U400, so, I’m not sure how I’d “fix” it, even if I had another signature analyzer.
Maybe someone like Ian Johnston or Kerry Wong or several others that we all know and love, could get this cutie up and running. Not this Bodger.
Unless some logic Guru comes out of nowhere and says something like “Yeah, just hold down the #3 button while you power up”, I think I need to carefully re-assemble things and stage it for whatever comes next. I will research Tektronix support options like any forums and see what I can learn moving forward, but yeah, this one’s going to have to park for a while.
As always, I really appreciate everyone’s comments!
Later,
JRH
PS - I see others have weighed in so I'll absorb those comments and re-evaluate.