Setting up a VAXstation

Liam Proven lproven at gmail.com
Mon Oct 8 12:30:04 CDT 2007


On 06/10/2007, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> > But as I said elsewhere, for my clients today, if a machine is less
> > than a couple of gigahertz, it's skipware. It's not worth my time to
> > try to diagnose a fault; if it fails, swap it out and replace it with
> > a new machine.
>
> Wait a second. Last time I checked, this was classiccmp. Not
> 'How-to-easter-egg-modern-PCs' or 'Computer-jobseekers' or... But
> classiccmp. It is ridiculous to assume that becasue something may well be
> the right solution in one case that it has to be right solution in all cases.

As have others, you misunderstand me. Clearly I should have spelled
this out more.

The fact that PC kit is so cheap that it's not worth repairing is not
why I don't repair classic machines. It's the reason I /don't know
how/ to repair classic machines.

> > my clients, not to nurse their old kit along as long as possible.
>
> As I said, this is classiccmp. Nursing old kit is exactly what we do here.

No... Classicmp is a mailing list. It's where people /talk/ about
classic kit. The nursing happens elsewhere in real life. Salient
difference!

> > I realize that. But I did specify earlier: I don't generally work
> > below the level of the circuit board. There's no single part of a PC
>
> Again, how on earth cna you know what the fault is if you can't diagnose
> it. You mentioned swapping a DIMM. How can you know if an intermittant
> memory problem is a fault in the DIMM or in the memory controller on the
> motherboard?

Well, although I realise that's just an example, I can respond using
details of a recent real job.

An AtlhonXP PC works fine with 2 DIMMs. With all 3 slot filled, it
crashes, freezes or hangs. I suspect, from prior experience, a memory
error. So step #1, I get a Linux boot CD with memtest86 on it, so I
can exercise the RAM.

With all 3 DIMMs fitted, memtest gives errors.
With 2 fitted, it's OK.
Try the 3rd on its own: fine.
Try the other 2 on their own: fine.
Try all 3 slots individually: fine.

Summary: any permutation of 2 of the 3 is fine. All the DIMMs
themselves check out fine, including on other machines. But on this
machine, filling all 3 slots makes it unreliable. Given that I don't
have a good motherboard to swap in, the resolution, then, is to
downgrade it to 2 DIMMs & warn the owner not to try 3.

That seems like a reasonable diagnostic process to me, and apart from
fitting or removing the DIMMs, the only tests were done in software.

> > I don't know what that is. I have a bag of ISA kit: mostly multi-I/O
>
> PGC = Professional Graphics Controller. An IBM board set (3 boards
> fitting into 2 adjacent ISA slots (there's a memory PCB sandwiched
> between them) that form an intellegent-ish graphics card with an 8088 to
> control it (!). I have the techref, I'd love to play with the boards.

Ah. Exotica. Most of my stuff is very vanilla, I'm afraid.

-- 
Liam Proven • Profile: http://www.linkedin.com/in/liamproven
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