Well maybe a little cleaning won't hurt. Wow that speedo had a hard life so far. Hope you get lucky and a good cleaning works.
A little silicone when you put it back together.
I did indeed try cleaning it up some, getting the corrosion off of all of the solder joints as well as using electronics cleaner, but unfortunately it seems she's just too far gone. It almost looks like it's been waterlogged for years, the 'cage' around the LCD display crumbled apart in my hands... wild stuff!
Now comes the decision as to what to replace it with- the standard Autometer Pro-Cycle is the closest replacement, and would match my tachometer the closest, but there's also the possibility of replacing both gauges with some from another manufacturer. I thought about digital, but I like the mechanical gauges personally because I like seeing the needles sweep lol.