HP27 Restoration (Lots of Corrosion)

[calc-calcs]

It lives again!

Received the new Panamatik ACT today after almost a full month of waiting for it to finally arrive, and I am happy to report that it worked on the first try. So the original ACT and/or the RAM chip where definitively toast as suspected.

On first test, all keyboard keys seem to respond and work perfectly without even a hint of bounce and all have the right click feel. Then tested all basic and most higher functions and all seem to be working as expected.

Guess now all is left is to break open the battery case and put in two new Eneloop AA cells. Have done this a couple of other times in the past, but on this occasion seem to be having a bit of difficulty fully separating the two halves of this stubborn battery case. Its been a while since I did this the last time but can't remember it being so difficult.

First used a sharp Xacto knife and went around and slightly into the whole seam. Then carefully using a very small jeweler hammer tapped the battery case from all lateral sides around the seam while wrapped in a protective cloth, but so far made very little progress in completely breaking the seam. There are some small areas of the seam that are starting to separate but there is about 80% still stuck together. I also seem to have hit a plateau with the tapping and for a while now have not made any further progress.

I wonder if carefully heating the plastic just a bit around the seam with a heat gun would help to facilitate the separation the seam with some more careful taps? I have even tried wrapping the battery case in the cloth and whacking it into the carpet, which always seems to work quite well to open sealed "wallwart" power supplies, but in this case that did not help either.

Anyone have any suggestions on this?

Attached a few pictures of the ACT installation and test.