The repair guides were good as they told you where to go looking on your board for your issue and saved you getting out the schematic and looking.. yep, the lazy way!
For SS repairs you only need a basic knowledge of TTL electronics. 7XXX chips etc.
 The logic is pretty much " gate open - gate shut"  and diagnostics can be done with a DMM and or logic probe.

But im with Beaky.. the repairs were seen as the be all and end all  repair guide and some of the stuff I just didn't agree with.