Hi Don,
the 596-4 board does have a battery soldered and hotglued between IC18 & IC19 as well like previously mentioned D1 & R1 in place and soldered. The preference would be not to re-install the patches everytime, so then I should just remove D1 & R1 if the battery is present, hypothetical question could this have affected the -5 rail? I've measured the T1 transformer and will check the L1 coil next but all other rectifying diodes check out ok. On, transistors I've tried to cross reference those parts but some more obscure parts came up..I will try to source the original parts on ebay this way I won't have any doubts.