Thanks fellas, glad to hear that L is still repairing them.
BUT, made a bunch of rookie mistakes while dealing with the scrolling problems and the Base not Found issues:
While checking the base, I inadvertently pressed the channel button; and, while checking the connection from the base to the ZWL, disconnected the base from the transformer. So, switched the base to channel 2 and re-scanned that into the remote; fixed the connection to the transformer; changed the batteries to a fresher Ni Hydride backup set and charged them.
Now, scrolling goes better, am not getting Base not Found. Will stress it a bunch today.
Many thanks to the forum members; got excellent help from the members that guided me thru repairing the smoke unit on my Big Boy in 2019 - extreme patience and step by step help.
Just for the heck of it, I looked on the Bay for a 990; most are North of 1K.