48G Destructive Teardown - EEVblog

[Eric Rechlin]

(05-23-2017 01:52 AM)Han Wrote:  The other oddity about that calculator was the jumper between ROM and RAM chip. The calculator presumably got upgraded to 128KB, but such an upgrade never required anything more than a RAM chip replacement.

In the video he said that the original owner damaged a pad when doing the upgrade, so that's probably why there's a jumper wire. I also got the impression that the upgrader didn't know what he was doing 20 years ago when he did the upgrade, which is why it looks like a complete mess during the teardown (just look at the faceplate).