The Kanga power boards are the same and the motherboards are mostly the same. I'm not 100% sure why those noises but I think it's a capacitor issue. As you've noted, when you leave it plugged in for a while it's more likely to do this. When I recapped the one cylindrical cap on my motherboard and the two on the power board, it mostly stopped. I mostly use a non-recapped power board so I forget if it totally stopped. But I have noticed it sometimes recurs on the non-recapped power board only when the PRAM battery or the battery are plugged in. So I think it's definitely an electrical issue, and probably with the capacitors on the motherboard - but it may be the result of electrical issues with the power board (and possibly its capacitors). It's also possible there's something wrong with the speakers. Or there may be multiple problems that yield similar symptoms.
No, I never plugged in or unplugged anything from this ADB port while the computer had power to it. I used to do that all the time (15 years ago) and never had a problem. Actually I did that a few months ago between my SE and PM 7100, before I was aware of the warning against that. But short-term, in my experience, hot plugging/unplugging wouldn't yield this symptom. In the long-term? Maybe. I don't know what happens to ADB over time with hot-plugging. And I wasn't the original owner of this computer so it's possible - though it seems a little odd someone would be using the ADB port on a 1997- laptop a lot. Who knows?
No, I never plugged in or unplugged anything from this ADB port while the computer had power to it. I used to do that all the time (15 years ago) and never had a problem. Actually I did that a few months ago between my SE and PM 7100, before I was aware of the warning against that. But short-term, in my experience, hot plugging/unplugging wouldn't yield this symptom. In the long-term? Maybe. I don't know what happens to ADB over time with hot-plugging. And I wasn't the original owner of this computer so it's possible - though it seems a little odd someone would be using the ADB port on a 1997- laptop a lot. Who knows?









