Know this is old, but don't see this tip anywhere else.
I've fixed a couple old ones by taking off the faceplate (four snap clips) and putting the plastic lens back in it's spot on the gyro.
Two gyros inside, both have two holes, one has a cross-looking built in piece, the other one holds a plastic lens. If the lens falls out, you just need to put it back in place.
For the two I've fixed, one just snapped back in, the other I had to dab a bit of superglue on one end to hold it.
Both are still working, it's been about a year (so I wish I'd noticed your post then lol)
One just quit working completely until I fixed it, but the other gave similar indications to yours, detected, but way out of place.
Bottom line, if it rattles when you move it around, might be a quick cheap fix.
