Drum Install Cannon NP 4050 (full details) if...

Question

I have recently aquired and older cannon copier (NP 4050)
It ran awesome for months with no problems.I had a local guy check it out (whom is no longer available) and his opinion was its time for a drum kit replacement..I dont have the manual or schematic so I seeking direction..I have brandnew drum in hand and ready to go....Thank you in advance...