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From: lphillips@lpami.wimsey.bc.ca (Larry Phillips)
Newsgroups: comp.sys.amiga,comp.sys.amiga.hardware
Subject: Re: Amiga Cancer
Message-ID: <2179@lpami.wimsey.bc.ca>
Date: 31 Oct 90 20:44:12 GMT
Lines: 75
Return-Path: <lpami!lphillips>
To: van-bc!rnews

In <90304.111049FCS101@psuvm.psu.edu>, FCS101@psuvm.psu.edu (FRANK C SMEEKS) writes:
>Hi I thought the first line would grab some attention, but this is the
>only thing that can describe the affliction with my computer. I have
>one of the early 2000's. A technician (good one I might add) has
>updated my motherboard somewhat but no success to solve the problem
>at hand. I have been trying to solve the following problem:

What is 'somewhat'? The main thing to watch out for is that one of the bus
driver chips (U602 I think), if it's a TI chip, requires replacement or a
resistor on one of the lines. This is a fix documented by CBM, and is part of
the upgrade to Motherboard rev 4.6.

> The 2090A hard disk controller will not work with my machine.
> Symptoms. When the card is plugged in and the computer is turned
> on the machine will not boot. Pull the card out and the machine
> boots up fine, save of course the problem where the first key
> you press doesn't register.

Remove C910 and C911 from the motherboard to fix this problem... another
documented fix for some early 2000s.

> The card works fine on two other
> machines everything from formatting hard drive to booting up with
> them. Just about every chip that can be pulled and exchanged has
> been done, etc...

Did you change the BUSTER chip? It's an important one in the Zorro bus scheme,
and a bad one will cause the symptoms you describe, as well as a few problems
that are less obvious.

Did you try the 2090 in other slots? By itself (no other peripheral boards
installed)?

> I am out of options at this point. The suggestion was
> made that I buy a new motherboard from Commodore.

Might be the best way to go if you can't find the problem.

> This problem existed
> when I bought the da** machine and I didn't discover it until now
> when hard drives for this machine are almost affordable. I would say
> the problem is the fact the driver is a SCSI but that isn't it because
> machine should boot either way with the card plugged in and no drive
> attached sine other machines boot fine.

Why would it being SCSI have anything to do with a failure to boot?

> I figure either there is
> something I don't know which is magic and someone else has come up
> with the solution or my computer does have a terminal case of cancer and
> needs a new motherboard.

There is little magic in hardware. There are problems that can be traced to
design, to a failing component, to a critical timing condition, and so on. Some
problems are easier to find than others, and some are _REAL_ hard to find.
Machines don't get 'cancer'. It only seems that way.


>  What do you guys think??????

Something is broken. Find the broken part or parts and replace it or them. It
is preferable from a money standpoint to replace the lowest cost identifiable
failing part, and if that's the motherboard, so be it. It is worth trying
everything you can to avoid it.

-larry

--
It is not possible to both understand and appreciate Intel CPUs.
    -D.Wolfskill
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|   //   Larry Phillips                                                 |
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