[Drake] R7-A Service manual

[kurt]

Greetings
I recently aquired an R7-A that came with an R7 service manual. I would like 
to have both  R7-A service and operators manuals, perferably originals in 
good or better condition, But I will take what I can get. I also have a 
couple of questions. Does anyone know the serial number where the R7 changed 
to R7-A?  And if the service manual changed at the same time? I have wanted 
to try an R7-A for some time and I'm looking forward to using it.
Thanks for your time and consideration:
Kurt
KU7RT