I have been unable to cross reference a pair of old Hitachi transistors #'s (K175) and (J55). Any specs. on these would help enable me to find a substitute as well.
Thanks, Cole Johnson
These are Mosfets 2SK175 and 2SJ55, and not being made any more. They are 180V, 8A, 125W devices and substitutes could be BUZ901 and BUZ906 (200V) or BUZ900 and BUZ905 (160V).