Hello, 

I recently found a JCM900 4500 series hi-gain dual reverb in mint condition. The serial is Y38091---I know that it was made in 1990, I was just curious past the "Y" what the remaining five digits might pertain to? I was really just intrigued by reading the history of these and was wondering if mine is one of the first few produced and if it would be possible to find out what tubes and components were used on this one. Also, is it possible to get a copy of the original manual? 

Thanks for any and all help! I love my 900.