Ramsey (U890) - Pin 15 (PWRUP) -> _FAIL MUST be at min. +4.8 Volt
AND
Gary (U150) - Pin 56 (Powerup) -> _FAIL MUST be at min.+4,8 Volt
if not -> the Board won't boot
check the Power Connector's for Oxyd/Black Surfaces, and if there is no space between the plug and the connector; often there are shacky/waggly
Next "thing" - ya wrote "...Reset is Low..."
Check the Adress- and Data Lines for broken/corroded traces; in most cases -> at U975 & U976 the Area "looks" good, but it doesn't good
-> that means - BOTH - Sides -> Top and Bottom
Check, if the "MDAT" Line comes up -> look and check the Traces from U975 Pin 13 to Lisa Pin 20 - if this Line/Signal is not present - Lisa get "stuck" and System won't boot