9 May
2016
9 May
'16
9:29 a.m.
On Sat, 7 May 2016, Mattis Lind wrote:
What are the failure modes of PROMs?
I had a PROM fail on the 11/45 CPU board. This PROM is responsible for the
Conditional Codes handling. There was one output that had failed. I think
that the output drivers may fail, because I was able to temporarily fix
the problem by adding a pull-_down_ resistor to the (open-collector)
output. That fix was unstable of course, and I ended up in replacing the
PROM with a GAL (ugly fix because the pinout doesn't match well, and there
is no space for a nice adapter solution)
Christian