6 Mar
2021
6 Mar
'21
3:29 p.m.
-----Original Message-----
From: Richard Pope <mechanic_2 at charter.net>
Sent: 06 March 2021 23:20
To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: 80286 Protected Mode Test
Rob,
There is probably hidden damage to the motherboard. The acid will
follow
the traces inside the board and consume them. There is
no way to stop this
kind of damage. Sorry for the bad news.
I should have said that I have found a few bad tracks and I have fixed them
by adding wires. Previously it would not even POST, but it does now. The CPU
is physically distant from the battery damage. I am trying to understand if
this particular test could fail due to external factors or not so that I can
then investigate if there are other tracks I need to fix.
Incidentally, my repair wires are done very badly, are there any tips on how
to do this well? I have ordered some wire wrap wire because I believe that
is what I should be using, but I haven't got the wire yet.
Thanks
Rob
GOD Bless and Thanks,
rich!
On 3/6/2021 4:59 PM, Rob Jarratt via cctalk wrote:
> I have a DECstation 220 (Olivetti M250E) which is failing POST on a
> "simple test of the 80286 protected mode". It says in a service manual
> I have that for this test the CPU is set in the protected mode, the
> machine status word is checked to see whether it indicates the
> protected mode and then exits protected mode. This test seems to be
> failing. Is there any possible explanation for this other than a
> failed 80286 CPU? Could there be any external reason? This board
> suffered some battery leak damage. Clearly the
> 80286 is working well enough to execute this diagnostic and send some
> text to the screen, so it basically works.
>
>
>
> Thanks
>
>
>
> Rob
>
>