VS511 SZ Circuit Board. 

Cross Reference Numbers:  33-0033A-K, 33-54385-K, 54385-01, 54385-02, 54385-03, 54385-04, 54398, 55053-03, 59-138-1685 and others.

Common chip numbers that can be replaced with this board (chip numbers are usually found on a large chip near the centre of the board):

VS511SZRL(x), VS511SR1(x), VS511SZR2 and others.