Broken speedo on 5k

["KEN" <kkaregeannes@hayes.com>]

I recently pulled the instrument cluster to have my odo gear replaced. I put
the cluster back in and the speedo will not work. I checked the cable connection
attached and reattached a number of times, etc. Checked the cable at the diff 
cover. Looked okay. When I pulled it loose, and looked, there appeared
to be two parts, a sender in the diff cover and a receiver on the end of the
cable( I assume it is a magnetic system).

Since it quit when I disconnected it, I assume the problem is at the speedo.
I made sure the engagement piece was fully extended and I seem to have a good
connection. I'm stumped. Any tricks to reattaching the thing? Any way I can test
the unit without taking the car apart again?

Thanks
-ken- (1988 5kSQ)