Well, I was cleaning the trackball in my PB 160 and apparently one of the IR sensors was not well-attached. One of the wire leads had corroded all the way through and the whole thing just popped off. So now I'm trying to figure out what the specs are on that IR emitter component so I can order the right part from Mouser. Anybody have a lead on technical specs, schematics, or any info on these? Worse comes to worst I might be able to find another small trackball and pilfer the component from that one's board. But dang, I was really enjoying playing with this computer this weekend, it's sad to see it become completely unusable again so quickly.