Setting up a VAXstation

[Tony Duell]

> 
> On 10/4/07, der Mouse <mouse at rodents.montreal.qc.ca> wrote:
> > > I am puzzled by people who want to run old hardware, but who don't
> > > want to learn to repair it to component level.

[...]

> 
> > > I can understand why
> > > people want to run the software under emulation (even if that's not
> > > what I want to do), but I am seriously wondering what extra you get
> > > from running the old machien _other_ than being able to fully
> > > understnad and repair the hardware.
> 
> Even back in the day, there were lots of folks who bought PETs and
> Apples and more, that didn't know a single thing about hardware
> troubleshooting and repair - 30 years ago, when it broke, they took it

I think you're somewhat missing the point. I can (alas) understand why 
there are people who use currently-available machines (both then and now) 
and don't understnand how they work.

I cna understnad why people are interested only in old software, not 
hardware, and want to run it under emulation on a modern machine

My puzzlement is with people who want to run the old hardware (not have 
to run the old hardware becuase it is part of some machine tool or 
something) but don't want to understand what's going on inside. What more 
do you get over running the software under emulation?
[..]

> One of the more important considerations is where I'd get spare parts.
>  I _could_ component-level-troubleshoot a SPARC 2 or a SPARC 5, but so
> many of the components are not generic TTL parts, I wouldn't approach
> the fault with the expectation that I'd be able to locate a
> replacement part except on another similar board.  I don't mind

Exactly. 'Another _similar_ board' (my emphasis). The point being the 
board doesn't have to be indetical, the same part might be used on 
another, more common, board. And even if you do have to take the part 
from an indentical board, you could do so from a board that's got a fualt 
in aother custom chip, thus either being able to use a 'junk' board or 
being abole to fix 2 machines from the same board-of-spares.

I do quite a few reparis on HP handheld calculators. There are very few 
standard chips in those. The point is, though, you can often take 
processor chips from related machine (the ACT -- Arithmetic Control And 
Timing -- chip from an HP21 will repair and HP67, for example). 

> replacing SMT parts, but in the case of most of the SMT ICs on a SPARC
> board, I don't know where I'd locate new parts.  Removing DIP parts is
> difficult from boards as complex as these; not impossible, but
> certainly lots more difficult than from a 2-sided 1970s micro.

As an aside, the most layers of any PCB I've worked on was 14 (or is it 
16, I've seen both  figures quoted), and that was in a 1968 machine. The 
good news is that all I had to desolder and replace were transistors.

-tony