[Heathkit] SB-610 IF CAs

[carl lowry]

Came across an interesting concept the other day in my
search for the 455kc IF CAN which is Heathkit Part Number 40-746 in the SB-610 Scope.
Friend of mine had built his SB-610 & in his Manual the three IF CANs
which are identified in mine as being 40-746 (low), 40-747 (mid) & 40-748 (High)
were all replaced with only  One IF CAN .. that being P/N  40-785.
His Manual had a Date on it of 1968.
When did Heathkit go to just one 40-785 CAN for all three different IF configurations  ?
I have always seen a variety of the above 3 IF CAs & never the 40-785 CAN.
73s
Carl, k4zrd