This oscillator module is copyrighted "SD S-66".It is composed of resistors, diodes, capacitors, transistors mounted on a heat sink and a transformer. Many inspection stamps on circuit side.
Manufacturer
Scientific Data Systems (SDS)
Identifying Numbers
Other number
127660
Printed in white at top of board on component side.
Other number
131813-C
Printed in black on white labelat left side on component side.
Other number
789 E
Stamped in black at top on circuit side.
Other number
WT10
Printed in white at top of board on component side.