Here we go.... (48G fixing and MEMORY UPGRADE)

[Han]

Your most recent photo suggests that the connector pads for the LCD screen on the PCB are not lining up with the corresponding signal lines on the screen itself. This is why you are getting garbled lines and rows and partial annunciators being lit.

If you look at the "rubber connector" that connects the PCB to the screen, you can probably make out where the rubber connector lines up with the twist tabs because they (the twist tabs) leave a slight indentation into the rubber connector. I find that this helps with the alignment of everything.

Another tip is to use a small piece of stiff clear plastic (or something similar) to place over the screen (overlay side) and some non-conductive material on the PCB side. Then use a small clamp or two to hold the PCB into place. The clamp(s) will make contact with the protective clear plastic on the overlay side (spreads the pressure onto the overlay so that the screen is not damaged), and your non-conductive material on the PCB side (I have metal clamps). Now you can test the alignment without having to use the twist tabs. Adjust until everything is perfectly aligned. Then twist the 6 tabs into place. This method allows you to adjust as much as you like without wearing out the twist tabs.

EDIT: Also, if you know for sure that one of those HP48's is not salvageable, then cut out the bottom portion of the case (the battery part) so that you can use a makeshift battery holder and not have to rely on alligator clips.