DEC 3000 (alpha) faultfinding

[Maciej W. Rozycki]

On Sat, 31 Mar 2018, Peter Coghlan via cctalk wrote:

> I ran the various tests provided by the different jumper settings on my second
> 3000 600 and I found that the memTest (no-cache) LongWord Memory Test (position
> 5, J3) failed as well as the tests involving the cache.  In an attempt to find
> which memory was failing, I swapped around the memory risers.  Bizarrely, the
> (no-cache) failures went away completely when I swapped around the front two
> risers.  The failures returned when I swapped them back.  This is very odd as
> the two risers appear to be identical and seem to be populated with identical
> SIMMs.

 Have you tried cleaning the pins?

 The riser connectors are the same style DECstation 5000/200 MS02 memory 
modules use and I had cases of ECC errors appearing with those which went 
away once thorougly cleaned with IPA.  Lone reseating didn't help.

  Maciej