This part is a kind of semiconductor called A70PF.
Function of this product has Service Manual.
Manufacturers : AOpen
Image and pinout :
Some of the text within the PDF file :
A70PF Service Manual A70PF(RX-777NS) 1 / 33 TABLE OF CONTENTS WARNING---3 A. IMPORTANT SAFETY INSTRUCTION---3 B. SPECIFICATIONS --4 C. TIMING CHART-5 D. ADJUSTMENT CONTROL LOCATION--6 E. ADJUSTMENT PROCEDURE-7 F. BLOCK DIAGRAM12 G. TROUBLE SHOOTING HINTS--13 H. BILL OF MATERIAL -- [ ... ]