TEKTRONIX 2246 OPT 1 MADE IN 1985 OR 1986


I need some help looking for Tektronix 2246 Opt 1Y Service manual that goes with Serial No. B045176.
I have a new Service manual that covers Serial No. B700100 and above (2246 1Y,2R)
Serial No B100100 and above (2246 MOD A)
But the prints above are different.
The A10 MAIN board and A16 PROCESSOR are different with Serial No. B045176 MADE IN 1985 or 1986.
Can you help me or tell how to get one of the early model of this 2246 Oscilloscope