If I need service manuals I usually go with SAMS Photofacts.
They usually have what you need. I looked in thier data base but, I didn't find your model.
They have a section for downloading their database of what they have.
h**p://samswebsite.com
Hope this helps. also good search engine for service manuals will help find places that can sell you manuals.
I believe that actual model is really
HP54502A and does have opt's.
if this is, there is site in UK that can help, but don't know how pricey it is.
Best I can do.
WA