I just uploaded a couple of extra documents that might prove handy for the AM503B.
“AM503B, AM5030, A6300 067-0270-00 Verification & Adjustment Kit 070-9352-01.pdf” instruction manual.
“AM503B - AM50XX Declassification Document rev4-1.doc” a MS Word document dated November 4, 2021. Interesting date since I first came upon it in March of 2019.
To drill down on AM503B documents in the Files section of this site be sure to enter the search term in quotes (i.e. “AM503B”) in the search field.