Live ROM board exit and dead QL result

[janbredenbeek]

This looks like a RAM fault on the first pass (when writing data to the memory).
If you can replace the ROM with Minerva you'll get more info about location and which bit(s) failed.
Otherwise it will be harder to locate. Does it occur almost immediately or after a second or so? In the latter case the fault will be in the second 64K bank.
Also check RAM chips for loose contacts, RAM chips which may get hot etc.