Hi,
Here is a not very good video which shows how someone replaced the batteries in a A33. While that is not your problem I know, what it does show , at 2 seconds into the video (''do not miss it - pause the video'') is that you can gain access to the unit by unscrewing a panel from the bottom and also that the batteries are plugged in via a connector (''this is shown later''), so that you can disconnect them, making it safer (prevent electrical problems occurring) while you are working on it.
Hopefully with the panel off you will be able to see how to gain access to the DC power socket to effect repairs or replacement.
https://www.youtube.com/watch?v=B8xLBT3BB0o
Hopefully this is of some help