One of the stumbling blocks that we face when we go to repair something is finding a service manual.  We can often find manuals and information from the manufacturers websites, but some older gear is harder to find manuals for.  There are several sites I have found that specialize in hard to find electronics manuals.  Some are free and others have a payment due, but when you really need something from a manual, a reasonable fee is not much bother in return for its help.  In the last few years I found a site that has a huge list of manuals and many of these are very professionally done reprints, good quality work.   Check for your next hard to find manual - especially on older vintage electronics.  Another manual site to try is - and they have listings and catalogs for download.  

  An odd one that I found lately is - where over 4700 manuals for government items can be found.  The premise here is that military manuals are not copyrighted and can be freely distributed (once you go through the trouble to find them).  So this site does not charge - ever.  Great idea!

  While you might think - I don't work on government equipment, stop and check - they have manuals on military editions of such common items as Collins Ham gear, Generators, rifles, and more.  It may take you a minute to find them, behind government or army nomenclature, but its still a great source - and easy to view online.