I just uploaded a scan of the full booklet Service Manual for Silver ST858L at:
It includes every page, including a vinyl player Silver SL8, so much of this was already availible using the Service manual https://boomboxery.c...service-manual/ by Ken, but that one really covers a later model than the original 1980 model. The full BOM list of capacitors etc. are also found inside.
best regards Arne