Removed broken lock from top drop board. The lock had been heavily painted over, freezing the bolt and cylinder in place, in addition the lock did not have a key. During the summer, mild attempts to remove the lock had resulted in separating the bolt and back place from the cylinder. No other progress had taken place.
Having a bit of time available after Avi, Hava, Aliza and Eitan left and before other activities, resolved to remove the lock. Using a piece of plywood to protect the drop board itself from the pressure, placed a socket large enough to allow the lock to slide into the socket hollow over the cylinder. Place a second socket, small enough to bear on the cylinder only on the other size of the drop board. Placed the drop board, plywood protective piece, and two sockets in the bench mounted vise in the basement. Significant effort was required to drive the lock out of the wood. Appears that the lock had been smeared liberally with wood glue or other adhesive before insertion. Should have drived the lock out from the other side.
The broken Yale lock will be replaced with a Corbin lock found in my father's desk.
Afterward removed the light "tack strips" from the interior side of the top drop board so that the board could be refinished well and the rather ratty looking screening replaced with new.