I'm also restoring a 3rd-revision Model 15 (with the relay, and with no TO-33s on the heatsinks). I think it's useful to get a list of known transistor substitutes. So far, we have:
Q101, Q102, & Q103; originally DTM6; substitute 2N5401 (closely matched for Q102 and Q103).
Q108 & Q112; originally DTM11; substitute NTE291
Q102 & Q111; originally DTM12; substitute NTE292
Q110; originally DTM14; substitute MJ15004
Q113; originally DTM13; substitute MJ15003
That leaves:
Q104; originally DTM9; substitute ??
Q105 & Q106; originally DTM8; substitute ??
Q107; originally DTM10; substitute ??
If anyone knows any good substitutes for Q104 through Q107, please reply.
I traced the gainstage amp board to ID the components, fixing three errors in the service manual, which had Q102 and Q103 swapped, and misidentified Q105 as Q107. Here's my result:
https://dl.dropboxusercontent.com/u/37073121/Marantz/AmpBoard.pdf
This is the first later-model Model 15 I've worked on. Are the missing Q109 and Q112 TO33's from the heatsinks replaced with something else elsewhere? Are they on the current limiter board?
I'd also welcome sources for replacements for the big 5450uF caps, C15 and C21.