I have just tried the solder fix above, in my 99 outback, my speedo worked once in a while and came back on briefly if I held down the trip button. The post above explains in detail the fix for the speedometer. I followed it an in a hour was able to get my speedometer working again...a few screws, keep track of electrical and a small delicate but easy solder on the circuit board.
It has been a couple weeks and the speedo works great.