AN/TNH-21 tape recorder schematic or manual needed
 

Any suggestions, pointers, and help greatly appreciated. This may not
be the right forum but I'm not sure what is!
I've acquired a 4-channel, 5 speed reel-to-reel audio recorder used by
the Navy and others for signal intercept and analysis. But I need a
manual or schematic to get it running - the only manual I have found
reference to was published by the National Security Agency.
It is AN/TNH-21, manuf by Video Research Corp, Riviera Beach FL
Photos at http://www.navy-radio.com/record.htm
cheers,
Nick