I was out of town for most of the weekend, so I wasn't able to get much done. I worked on getting bluetooth audio working and so far that has been a bit of a challenge, but still appears to be within the realm of possibility. On the presumption that I'll get it working, I have been looking at some alternate layouts inside the calculator. Because of leaving out the audio board, I decided that I could probably now fit a USB port that will go directly to the raspberry pi onto the calculator, but I haven't decided if the HDMI port will be where the audio port was or if that's where I'll place the USB port. I went ahead and ordered a couple of micro usb breakout boards to use for the port that are slightly different sizes because I'm not sure which will end up working best.

There was an adhesive on the board from where the LCD ribbon cable was attached. I didn't have any Goo-Gone, so after looking through what I did have, I ended up using some acetone since the only think I know it to dissolve is ABS and just to be sure it didn't have any ill-effects on the circuit board, I tested it on the TI-86 board and it was fine. By the way, I do know that one thing you don't want to use on circuit boards is ammonia because it will dissolve the green solder mask on many boards. Anyways, I tried in on the TI-83 board and it removed the adhesive just like I hoped. It also cleaned the board really well and it looks great.

Next, I finished mapping out the wires to all of the solder points where I was attaching wires into vias. I ended up taking a 25-pin computer cable and using wire from that so that it would all be consistent gauge, yet different colors. It took me about an hour to solder all the wires in place while taking care to not have any solder gaps. I placed all of the calculator keys back into their appropriate places (they had fallen out previously and I put them into a ziplock) and screwed the circuit board back on.

The next steps will be to solder all of the other wires to the Raspberry Pi and then to star writing some kind of driver for it. Hopefully it will end up being easier than it seems, but I'll see. I think I came across something I can use as a starting point and then I'll flesh it all out. Also, I need to test that there were no shorts in the soldering job and I'll do that shortly before soldering the wires to the Raspberry Pi. Another small issue I need to contend with is all of the wires ended up right below where I was planning on putting the Raspberry Pi. That may not end up being a big deal though.