Odd Software for Odd Jobs

Resurrecting an 80386SX

I got a generic 80386SX machine on eBay some time ago because it had both 5.25" and 3.5" drives which would allow me to transfer old floppies to newer disks. It was built in Australia by a company called "Total Peripherals Group" … they are still around as tpg.com.au, now a rather large telecommunications provider!

2016-08-21 06.53.29

Every time I would start it up, it would complain that the CMOS settings weren't set. This was obviously because the backup battery had died sometime late last century.

So I thought I might as well sort it out.

Looking at the current battery, it doesn't look too healthy. In fact it appears to simply be three 1.2V button cells packaged end-to-end.


I de-soldered it simply enough - the positive terminal (right side) had already leaked some nasty stuff onto the motherboard so the whole pad came away:


Not to worry - I re-drilled the holes with a 1mm drill bit and then soldered on my brand new Lithium 3.6V battery (Jaycar part SB-1771). It's slightly larger than the three button cells so I ended up mounting it this way:


Not a bad job I think! Put the motherboard back in, reseated all the plugin cards (drive controller, VGA graphics card, serial/parallel ports, GPIB interface) and it came up good. I also gave the 5.25" drive a good clean too, including the heads, as it had been giving read errors. Works a treat now. Going to get a CF-IDE adaptor as I'm a bit worried the hard drive will just die one day. I've got two CF drives running in my old Amstrad PC1640 (8086 machine).