Did you end up trying anything yet? Isn't there some requirement for a working battery for it to power on or was that just the power routing through the battery so a corroded one isn't a simple run without it fix? -------- Original message --------From: Chris Pye <pye at mactec.com.au> Date: 11/26/16 12:26 AM (GMT-06:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Macintosh Portable Does anyone know off hand what polarity that Mac Portable requires? I know that the original was 7.5V @ 1.5A, but not sure of the polarity.