I bought an early Packard Bell laptop (1991), but it has an odd power supply socket and didn't come with a PS. It lists 5.6V and 7.5V on the sticker. I am trying to figure out how to build a PS for it. So far I have taken it apart and removed the power daughterboard. By sending some voltage through the larger pins in the socket I was able to figure out which one powered the battery connections. I am assuming that that is probably for 7.5V and the other large pin is for 5.6V. I am guessing the third smaller pin is for some sort of "power good" signal since it is connected to a small trace on the board. Does anyone have any experience with this laptop? I couldn't find anything besides some reviews on google.

By supplying 7.5V to the battery pin I was able to charge the battery and it does at least boot up even though it needs a new HD. However, it doesn't seem to draw anything from what I assume is the 5.6V line. Only from the battery.

Worst case I was thinking I could remove the big ole 4.8V nicad cylinder battery and perhaps supply 5V 3A directly to the battery terminals when I wanted to run it.