Why is my Amiga 500+ not booting?

Hi, I should start by saying I’m 19, so older home computers were already dead by the time I started using a pc, but I have a passion for these older machines and I have learnt a little about them over the last year or two, though are still unfamiliar due to lack of use of them.

I recently got my hands on my dads old A500+ and it turns on, but won’t boot into Amiga DoS or Workbench(I believe it would have been Workbench 1.3 in ‘91 when this model was made).

It turns on, the drive light goes orange, the little motor in the drive turns a couple of rotations and it stops dead and the light goes off

I have found the battery for the RTC has leaked at some point between 1991 and now, and on top of that has corroded part of the audio filtering system, Chip U12, GARY (completely corroded the pins facing the battery) and I believe another connection or fuse or something in between U12 and the battery

However I don’t have a soldering iron so I can’t remove these as far as I’m aware, nor do I know what these chips do. GARY is next to PAULA which I assume means it’s some sort of expansion to the original A1000 audio chip??

If anyone can help that would be amazing, I’d love to get this thing working again for preservations sake, but also to learn the system and make some games for it