> -----Original Message----- > From: Richard Pope <mechani...@charter.net> > Sent: 06 March 2021 23:20 > To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General > Discussion: On-Topic and Off-Topic Posts <cctalk@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 > > > >