It may be too late for you to see this reply but my manual for the AA-1640 list the 417-847 transistors as RCA 1B05 s
Hope this helps if your still looking for an answer.
George
Hello,
Looking for 417-847 transistors for the heathkit AA-1640.
Can't seem to find any.
Any suggestions?
Jeff
The Motorola MJ 410 is very close and works well.Look for it or whatever will sub for it as the 1B05 was limited production any way.You sometimes find them in Crown DC-300's.The RCA 2N5840 is a commercial version and will work great but they suffer from being tough to find too. Best shot if you need all 20 would be the MJ 410 or it's sub