23 Sep
2008
23 Sep
'08
4:57 p.m.
At 02:40 PM 9/23/2008, Rick Bensene wrote:
So, I'm suspecting a few potential areas to look at
one the RK8E:
A) Omnibus interface chips may be bad (bus drivers/receivers)
B) Data break logic (falsely asserting single-cycle data break when it's
not valid)
C) Timing/Control circuitry
Could be any of the above; what I'd do for starters is to pull the RK8E
and insert the boards one at a time. You might find that only one of
the boards breaks the bus; that may cut the number of possible problems
by a third. The RK clearly won't work that way, but it's a potential
way to troubleshoot.
(After that, divide and conquer to narrow down the problem further by
masking pins on three of the four edge connectors.
If you get to the point where you've identified the dead component and
need 8881s, SP380s, etc. I have a few that you could have.
-Rick