A blatant plagiarism of Kjelt's title, and it worked for him
In the 3468A thread I relied to a question about the 3478, pointing out that the 8039 program ROM was available e.g. from k04bb, but that there was also a mask-programmed 8048 micro in there as well, and that I didn't think there was any way of reading that code.
Well, I'm pleased to say that I WAS WRONG
It seems that the 8048 responds to the same sequence that is used during the verify phase of programming the 8748, so we can get the code. Then in the case of an 8048 failure, it could be replaced by an 8748 (if you can get one) or an 8039 (11MHz rated) with a piggy-backed EPROM.
I don't have a HP3478A to read this code from, BUT SOMEONE SHOULD DO IT.
Just saying....