Re: PDP-11/45 RSTS/E boot problem

[Paul Koning via cctalk]

> On Feb 13, 2019, at 3:54 PM, Ethan Dicks via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> ...
> It's interesting that it was a bad 7430 in yours.  I find that for
> equipment of that vintage, my usual suspects are failed 7474s and
> failed 7440s, probably 80% of the total.  Behind that, it goes 7420s
> and then maybe 7430s.

When our 11/45 failed in the MMU in 1975, my classmate Josh Rosen traced the 
failing path on the schematics.  When Jim Newport the field service engineer 
showed up, Josh described the diagnostics result that pointed at the failed 
path, and added "This is the failed chip" (pointing to one particular chip.

Jim asked "Why that one?"  Josh answered "because that is the most expensive 
chip".

It turned out he was right.

        paul