BRAVO - another DIY guy!
That's a decent scope for our purposes. See if you can get the card cage out of there. You may need to remove the PS too or extend the cables.
On the "Professionalism" - I'm just trying to save you the "experience" of turning a nice board set into a pile of junk with 2 seconds of misplaced enthusiasm. I've seen it too many times. NMOS is not as "immune" as later technologies to mistakes. That said, it's your option and your risk. Go for it!
You'll need to acquire some DIP CLIPS. An assortment of sizes - 14, 16, 20 will help with this job - more if you plan to continue this hobby.
44B - I suspected. There's a dirty little secret in Air Force procurement circles - once they approve "hardware", it's a big deal to revise it. Most manufacturers get around this by simply re-labeling new versions in the nomenclature of the old "approved" ones. This practice may be behind this to a degree.
It indeed would be nice to have a schematic for this board [a 44B]. I've been looking in all the unusual ways that have worked for me in the past. One of my favorite ones was to follow google links to surplus DEC parts houses. Some of them used to have downloadable copies of the documentation sets for these products, as it was customary to include them in the past. Unfortunately, there seems to have been a change in the time-space-continuum recently - all the links to these documents have silently disappeared from Google results and from these vendor sites. [Foreshocks of SOPA and PIPA?]
However, in the absence of this documentation, we can proceed anyway. Troubleshooting without a schematic is a bit of an art form, bordering on "black magic" at times, to it's not exactly easy.
Begin by making yourself a good, comfortable place to work [seated]. Provide plenty of table space. Make it a spot where it can be left setup between sessions. [away from curious hands and paws] Gather your equipment around you. When you have the cage sufficiently accessible - you're ready to begin.
Prepare to take copious notes. [I make "Project Notebooks" in loose leaf binders] Print out part outline sheets [I use photoshop to make these] with ruled and labeled fields. If possible - include device designations. Leave plenty of room for hand-written scribbling. If I were you, I'd figure out a way to label individual RAM ICs so I know where they started out once they're pulled from sockets. Maybe you can mark em as we pull em, or maybe a sorting bin? [there's only 36 after all]
In the meantime, I'll try to work out some testing software to exercise the individual chips. It's not ideal using ODT for this, but unless we have some target system memory that WORKS, we can't do it the better way of running a program on the target CPU from memory.
Lou will have a lot of good advice - he's got this RAM repair gig down pat. I tend to overdo it and prepare for the long haul.
