Lunch box Portable

So another neglected PC showed up on my doorstep recently.

A 386 "lunch box" portable.  The "lunch box" form factor was short lived as computer hardware and batteries got better and the "lunch box" was dropped in favor a regular laptop.

This old guy has an 80386, 80386sx co-processor, 5 GB RAM, 1.44 MB floppy, 40 GB MFM hard drive, red plasma monochrome display.

It actually started up (but the first power up shot out a spark but didn't seem to cause any problems - more on that later) but would not boot.  As expected, the hard drive was done.  So on to the disassembly.

It was obvious that this had been stored on concrete.  Concrete is porous and allows moisture to flow through it.  If you need to store things on concrete, it needs to be on top of something between it on the concrete.

Rust.  Lots of rust and oxidation.  I had to completely dissemble the power supply and de-rust the housing.  Even then, I had to end up spraying it with Rust-oleom just to keep the rust down.  That's where the spark came from - a piece of rust across some high-voltage lines.

So, that done, I moved on to spraying some of the places with deox-it, reseating several chips.  The 386sx had lots of oxydation - which caused issues with booting and even getting into the CMOS.

Oh, that's another thing.  The CMOS battery had died long ago and the previous owner had replaced it with regular alkalines - which he never removed before storing.  Ya, that toxic mess went into the trash.  I've made another alkaline pack, but I'll figure out how to handle the long term after I get it all working again.

Now I get a consistent boot and into the CMOS.

The MFM controller is gone.  It was too hard to find an MFM replacement, so I got a IDE/floppy controller card.  I have an IDE/CF card adapter coming soon to replace the hard drive.

The floppy drive had issues.  I didn't look too far into that yet.  I just grabbed my old 1.44 floppy drive from the display case and tested that out.

I tried DOS 6.2 and no go.  I kept going down until I found that DOS 5 will work with some issues (but they seem disk drive related).

So at this point, I have a consistent boot from floppy.  I'm going to try to removing the external floppy setup to see if I can get more reliability from the floppy drive.

I also disassembled and cleaned the keyboard.  So reassembly is next on the list today.