Hey,
Yeah it's certainly possible, but I don't think a guide exists to help you identify the traces or regions easily.
I'd suggest looking at the service guides and manuals that describe the tests. There's about a paragraph of text per test that describes what the test does. There's also a general theory of operation section that describes roughly how the LAs work. You can use those, in combination with looking at the board, to help you figure it out.
Some tests are more useful than others. For some of the memory tests, for instance, they will identify which chip number is failing a test. That chip number isn't specific as a PCB silkscreen Unit Designator (or whatever the Uxx's are called) --- so you have to count chips to figure it out.
I can't easily look this up at the moment, but turning on enhanced debugging can help. There's switches like "d=9,p=9,r=9" that adjust the verbosity of the debug output. I don't think we've found a guide that describes what they do, but I think we assume 0-9, and I think I've done 255 before because why not? Look back through the previous threads here where they are discussed. You can see them at the command line help.
Sometimes, you can see a particular problem that matches to a trace. For instance if bit6 is always 0, when it should be a 1, then that trace could be cut. If things are intermittent, it's less clear. Now which trace is bit6? It's mostly trial and error. With these custom chips, finding datasheets isn't always possible. But things are logically laid out on the PCB, usually. So if it's an 8-bit bus, and you know it's bit6, then count 6 from the left, and 6 from the right.....it might be one of those!
You need to be able to probe the boards live, while they are plugged in. In order to confirm the right voltages/signals when the board is being tested/used. MarkL on these forums is a super smart guy --- he has techniques like installing the board in the bottom slot, flipping the chassis over, taking off the bottom cover, then probing the board.
For full disclosure, while I know the approximate technique on how to fix this stuff, I've never actually done it. There are physical challenges (access to the board while it's powered up), which also can require small pigtails to be soldered to the chips.... This stuff being SMD can be challenging to avoid shorts. Or you need to use microprobes (really small fine clips for legs of chips) which can be expensive.
I attempted repairing a couple bad boards, but it was pretty obvious it's beyond me -- partially in terms of lack of experience and skill, but mostly in terms of patience and willingness. You might be in a different place with all of that, obviously.
I hope this helps
Keith