No where in any of your previous posts above do you state that number or any other manufacturer's number.
But, here is how you second source a transistor:
1) Enter the PN in the search engine and start looking for it's data sheet or electrical specs.
2) once you know the key specs of voltage rating, collector current rating, gain and case style you go to transistor makers like motorola and shop for a power transistor similar to it.
If you can't identify the number, you estimate the needed specs based on surrounding circuitry, load current, etc.
BTW: on the schematic, there is an actual part number listed under the part labeled R265A device which is: 2N1309
I can't find any transistor on the schematic labeled R256A, which is the number you list above.
EDIT TO ADD: the 2N1309 is a germanium power transistor. I don't even know if germanium transistors are still available?
2N1309 pdf, 2N1309 description, 2N1309 datasheets, 2N1309 view ::: ALLDATASHEET :::