Subj : Re: 286 gang
To   : dingo
From : boraxman
Date : Tue Apr 15 2025 15:09:46

 di> 
 di> On Monday, April 14th boraxman said...
 di>  Bo> error on boot.  Not  been able to resolve the issue, but there is a b
 di>  Bo> of corrosion around the motherboard where the CMOS battery was. (it 
 di>  Bo> leaked it seems).
 di> 
 di> if it is ruined by corrosion, unless the damage is too great, you can
 di> visually inspect the traces, from which pin it is from and where it
 di> should go, and you can solder "bodge wires" to complete any traces that
 di> are incomplete. You can also solder copper wire directly onto the traces
 di> to bridge the spaces they are broken.
 di> 
 di> I say it like its easy, but I tried to repair an Apple ][+ board that had
 di> battery corrosion (from a 3rd party thunderclock card), but I put hours
 di> of work into it and there was still "something" wrong with it. Instead
 di> of buying a nice digital oscilloscope for several hundred, I repaired it
 di> by buying a fully complete, chips and all Apple ][+ board fully tested
 di> for under $100..
 di> 
 di> My first computer was a 286, and I shot it up with a bb gun during a
 di> power outage as a teenager. I wouldn't recommend a 286 for anyone... the
 di> "games" were really bad for that CGA graphics era...
 di> 
 di> You do probably have a working 5.25" disk drive, and that can be
 di> restored and  reused with a GreaseWeazle, "The Greaseweazle board is
 di> compatible with any [..] Standard floppy drive, that includes any 3.5
 di> and 5.25-inch drive with a 34-pin  connector"
 di> 
 di> https://github.com/keirf/greaseweazle
 di>  
 di> You can then image from and to floppy disks for all the other 8 and
 di> 16-bit systems of the era, lots of archive.org work has been done to
 di> make these "flux" images of floppy disks available. This technique also
 di> allows reliable duplication of "copy-protected disks"
 di> 
 di> 

I tested the traces with a multimeter, and they all seemed functional.  The
corrosion did not appear to, at least from my testing, affect the PCB all
that much, but I may have missed a spot elsewhere.  Gate A20 error actually
relates to the keyboard somehow.  While I don't really need the 286 working, as I have a couple of other 486s to serve as my "legacy" machines, it would be nice to get this working so I can use my CGA card and my old CGA monitor.

As for 5 1/4 inch drives, I have a few, but only the HD variety.  I lost (quite literally just lost) the 360K drives I had with my XT.  Have no idea where I put that machine.

I've already imaged most of the disks when I could, but only data dumps, so
just writable disk images.

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